APPLIED CHEMISTRY FOR NURSES THE MACMILLAN COMPANY NEW YORK • BOSTON • CHICAGO • DALLAS ATLANTA • SAN FRANCISCO MACMILLAN & CO., Limited LONDON • BOMBAY • CALCUTTA MELBOURNE THE MACMILLAN CO. OF CANADA, Ltd. TORONTO APPLIED CHEMISTRY FOR NURSES BY STELLA GOOSTRAY, R.N. EDUCATIONAL DIRECTOR, TRAI^NG SCHOOL FOR NURSES, PHILADELPHIA GENERAL HOSPITAL AND WALTER G. KARR, M.S., Ph.D. CHIEF CHEMIST, LABORATORIES OF THE PHILADELPHIA GENERAL HOSPITAL, ASSISTANT PROFESSOR OF BIOCHEMISTRY, GRADUATE SCHOOL OF MEDICINE, UNIVERSITY OF PENNSYLVANIA THE MACMILLAN COMPANY 1924 Copyright, 1924, By THE MACMILLAN COMPANY J Set up and electrotyped. Published September, 1924. Printed in the United States of America by J. J. LITTLE AND IVES COMPANY, NEW YORK PREFACE The authors endeavor in this book to give the elementary foundation principles of chemistry which will be of service to the nurse in her work. We recognize that the average training school for nurses has students with a diversity of educational backgrounds. In preparing this book the authors have had this in mind. The effort has been made to present the material so that it may be grasped by the student who has had no chemistry and at the same time serve as a review for the student who has covered an elementary course in chemistry in the high school. The general principles of Inorganic Chemistry are given and such Physiological Chemistry as will give a basis for the more intelligent understanding of the physiology of the human body. Enough advanced material has been given, we believe, to make the book of practical value to the student who has had advanced work in chem- istry but who now needs to have the applications made to her work as a nurse. No satisfactory course in chemistry can be given without individual laboratory work by the student. Experiments have been included from which the instructor may choose according to the amount of time at her disposal. The Laboratory Manual is a compilation of experi- ments adapted from various sources. We are indebted to Miss Mary E. Norcross of the Philadelphia General Hospital for the drawings. CONTENTS CHAPTER PAGE I Physical and Chemical Changes . . 1 II Elements, Compounds and Mixtures . 8 III Oxygen and Oxidation 25 IV Hydrogen and Its Oxids .... 37 V The Kinetic Molecular Hypothesis. The Gas Laws 43 VI Water 49 VII Electrolysis and Ionization. Acids . 58 VIII Bases, Acid and Basic Oxids ... 67 IX Inorganic Salts 73 X Common Metals and Their Compounds 83 XI Important Non-Metals and Their Compounds 93 XII Carbon and Its Oxids 102 XIII Organic Chemistry 108 XIV The Chemistry of Foods . . . . 126 XV Digestion 141 XVI Metabolism 149 VII VIII CONTENTS CHAPTER PAGE XVII The Blood 155 XVIII The Chemistry of the Tissues . . . 165 XIX The Excretions 173 Review Questions 179 Laboratory Manual 193 APPLIED CHEMISTRY FOR NURSES APPLIED CHEMISTRY FOR NURSES CHAPTER I Physical and Chemical Changes "A science teaches us to know, and an art to do, and all the more perfect sciences lead to the creation of corre- sponding usefid arts. . . . Chemistry is the basis of many useful arts."-Jevons. Chemistry is the science which treats of the com- position of substances and of the transformations which these substances may undergo. If we analyze our defini- tion we find that a science is a classified body of knowl- edge which has been proved and accepted, so that we shall study what has been proved about the composition of many common substances. We shall learn to know the given conditions under which certain substances will always behave in a definite way, so that we may apply our knowledge with profit to our work as nurses. It was not until the end of the 17th and the beginning of the 18th Century that there was the development of chemistry as a science, although the various nations of antiquity, especially the Egyptians, had vast stores of practical and valuable chemical knowledge. During the mediaeval period, the alchemists delved into the mysteries 1 2 APPLIED CHEMISTRY FOR NURSES of the "occult art," trying to discover how they might change the baser metals into gold and silver, and others added to their quest the search for that which would in- definitely prolong human life. It is interesting for us to note that Paracelsus, who lived from 1493 to 1541, said that the true use of chemistry was not to make gold, but to prepare medicine. The modern science of chem- istry seeks wider fields of usefulness. The high school has its chemical laboratory, that it may give to its stu- dents not only the cultural value of chemistry but also training in accuracy of observation and in making scien- tific conclusions. The industrial plant has its chemical laboratory for research in its own special industry; the agriculturist turns to chemistry for a knowledge of the soil and its fertilization. The modern hospital to-day not only uses this science for the compounding of drugs but it has a biochemistry laboratory that the wonderful de- velopment of this science in relation to the life activities of the human body in health and in disease may be used in the service of its patients. Importance to Nurses.-Chemistry not only reveals the reason for the changes which are taking place all about us, but a knowledge of chemistry is a basic requirement for an intelligent understanding of anatomy, physiology, practical nursing, bacteriology, materia medica, dietetics and hospital housekeeping. It gives the nurse another tool for the perfection of her art in all its varied ramifica- tions, since every art must have a sound theoretical basis. The human body is a laboratory wherein chemical changes are taking place constantly; life processes, from begin- ning to end, involve chemical change, and the nurse deals PHYSICAL AND CHEMICAL CHANGES 3 with human life. Not a day passes in the professional life of the nurse that she is not called upon to do some work or supervise some work where she may apply her knowledge of chemistry and thereby conserve health, time, and energy. As we go on in our study we shall try to apply the principles of elementary chemistry to our own professional field. Branches of Chemistry.-There are various branches of chemistry, but the basis is inorganic chemistry. Inor- ganic chemistry covers the study of all the elements, ex- cept carbon, and their compounds, and through its study the principles of chemistry are learned. Organic chem- istry is the study of carbon and its compounds and covers a vast field with many subdivisions. Matter.-A previous paragraph contained the statement that we are to study the behavior of "substances." A substance is any definite variety of matter and all sam- ples of it show the same characteristics or properties. Matter is that which occupies space. There are three kinds of matter, solids, liquids and gases. Wood is a solid; it has a definite shape and definite volume. Water is a liquid; it has no definite shape but definite volume. It takes the shape of the vessel that holds it. We can see these and know for ourselves chai solids and liquids occupy space, but many of our gases are colorless. Air consists of a mixture of gases. A gas has neither definite shape nor definite volume but entirely fills the container in which it is placed. When we inflate an air cushion or an air bed we fill it with a mixture of gases, so that we know that gas occupies space. The form in which matter exists is its physical state and physics teaches that the physical 4 APPLIED CHEMISTRY FOR NURSES state of a substance is dependent on temperature and pressure. It is a common observance to see a solid changed to a liquid by raising the temperature or a liquid changed to a solid by lowering the temperature. A liquid may be changed to a gas by raising the temperature or lower- ing the pressure. The temperature at which a solid changes to a liquid is its melting point, from a liquid to a solid, its freezing point. A liquid evaporates at all tem- peratures but the evaporation increases with increase in temperature until finally bubbles of its vapor form throughout the liquid and the evaporation becomes very rapid. This is known as the boiling point. At this point the temperature remains constant until all the liquid has disappeared. The process of changing from a liquid to a gas is known as vaporization. You have all seen the steam from a tea kettle on a cold day strike the window- pane and condense or form drops of water on the cold pane. The changing from a liquid to a gas and back to liquid is known as distillation, and in our operating room we make use of this process to remove impurities from water, as we shall see later on in our study. A solid may be changed directly into a gas without the intermediate stage of the liquid and back again to a solid. If iodin crystals are heated they do not liquefy but immediately give off a purple vapor, which when it strikes a cold sur- face becomes a solid again. This process is called sub- limation. Identification of Substances.-When we want to know about a person we usually ask two questions. First, "What does he or she look like?" In other words, we want to know the physical appearance of the person. Secondly, PHYSICAL AND CHEMICAL CHANGES 5 "What is he like?" or if we put it into scientific form we would ask "How does he behave ?" So, too, with the substances we are to study in chemistry. We shall ask practically these same questions. "What are its physical properties?" or in other words "What does it look like?" "What is its color, taste, odor, solubility in water, its density?" Secondly, "What are its chemical properties," or "How does it behave ?" Physical Change.-Substances may undergo two types of change, physical and chemical change. In a physical change we have an alteration of the properties without the formation of any new substance. A magnet will withdraw a piece of steel from the eye; the magnet at- tracts the steel but when the magnet is removed from it there is no change in the steel. There has been a change in the magnetic condition, but it has been a temporary change. Take a very simple procedure in practical nursing. When you twist a rubber glove to inflate it with air, in order to turn it, you temporarily change the size of the glove; when the air is expressed the glove is unchanged. A galvanic battery may be connected with a piece of iron and we see the difference between this iron and a piece through which no electricity is passing. When the current is turned off, the iron is as it was before. Ice melts at a certain temperature and water freezes at a cer- tain temperature. There is no change in the inherent, nature of the water but merely a change in form. All these are physical changes, so that we may have changes in position, magnetic condition, size, state, form, electrical condition and temperature, without affecting the inherent nature of a substance. 6 APPLIED CHEMISTRY FOR NURSES Chemical Change.-A chemical change is one in which a new substance or substances are formed which have definite specific properties different from the original substance or substances. We may have a very vivid dem- onstration of this by taking a few c.c. of bichlorid of mercury solution in a test tube and adding to it a few c.c. of potassium iodid solution. Normally they are both colorless solutions, unless the bichlorid of mercury has been colored by a dye as a precautionary measure. When these two solutions are put together a definite change takes place. There are very finely divided particles of a solid in the tube, red in color, and a chemist would tell us that we now have red iodid of mercury and a solution of potassium chlorid. A nurse is instructed never to give two medicines to- gether which change color or form a precipitate. Here we have a reason for it. A precipitate is a solid which is formed as the result of combining two liquids. A chem- ical change has taken place. The physician has ordered each drug for a specific purpose and should the two drugs be combined and a chemical change take place, new sub- stances have been formed which may have an entirely dif- ferent action from that which was intended. Outline for Study I. Introduction a. Chemistry defined b. History c. Importance to nurses d. Branches of chemistry II. Matter a. Defined PHYSICAL AND CHEMICAL CHANGES 7 b. Physical states c. Change in physical states d. Definitions (1) Melting point (2) Freezing point (3) Boiling point (4) Vaporization (5) Condensation (6) Distillation (7) Sublimation III. Identification of Substances a. Physical characteristics b. Chemical behavior IV. Physical Change a. Defined b. Its nature c. Types V. Chemical Change a. Defined b. Its nature c. Practical application CHAPTER II Elements, Compounds and Mixtures All matter may be classed into two groups, pure sub- stances and mixtures, and the former subdivided into elements and compounds. All three, elements, compounds and mixtures may exist as solids, liquids or gases. Elements.-An element is a substance which cannot be reduced to any simpler substance, so far as we know at the present time. There are about 80 known elements and of these we have in our own bodies at least fifteen, however, seldom as free elements. The following is a list of those in the body as well as some of the other elements in common use, either free or in compounds. The ele- ments in the body are listed according to the percentage in the body. In the table on the opposite page the physical state of these various elements when free is given and also the symbol which is used for them. Based on the chemical action of the elements we may group them into two classes, metals and non-metals. The names of these elements are from various sources; some were given by ancient alchemists, because they be- lieved they possessed certain chemical characteristics or from other characteristics, as for instance, bromin from its odor, iodin from the Greek word for violet, since a 8 ELEMENTS, COMPOUNDS AND MIXTURES 9 Element 3 er cent in Physical State when free at or- dinary Tem- perature Metal or Non-metal Body Symbol Oxygen 72.0 0 Gas Non-metal Carbon 13.5 c Solid Non-metal Hydrogen ... 9.1 H Gas Non-metal Nitrogen .... 2.5 N Gas Non-metal Calcium ....') Ca Solid Metal Phosphorus . P Solid Non-metal Potassium K Solid Metal Sulfur S Solid Non-metal Sodium Na Solid Metal Chlorin 1 3 Cl Magnesium .. Mg Solid Metal Iron Fe Solid Metal Fluorin Fl Gas Non-metal lodin I Solid Non-metal Silicon •> Si Solid Non-metal OTHER IMPORTANT ELEMENTS Bromin Br Liquid Non-metal Arsenic As Solid Non-metal Bismuth .... Bi Solid Metal Boron B Solid Non-metal Lithium Li Solid Metal Strontium .. . Sr Solid Metal Barium Ba Solid Metal Radium Ra Solid Metal Zinc Zn Solid Metal Aluminum .. Al Solid Metal Nickel Ni Solid Metal Copper Cu Solid Metal Mercury .... Hg Liquid Metal Silver Ag Solid Metal Tin Sn Solid Metal Lead Pb Solid Metal Platinum ... Pt Solid Metal violet vapor is produced when it is heated. Others have been named for the place where they were first found. Symbols.-In order to indicate an element in an abbre- viated way, symbols are used. Some are simply an initial 10 APPLIED CHEMISTRY FOR NURSES letter, as for instance Oxygen, O, Carbon, C and Hydro- gen, H; or the first two letters of the word, as Ca for Calcium; others, the initial letter or the first two letters of the Latin word as Na for Sodium, from the Latin word Natrium or K for Potassium from the word Kabrium. Atoms.-Elements consist of minute particles called atoms which cannot be further divided by any chemical means. The symbol represents one atom of the par- ticular element. We said that elements are pure sub- stances and this is because every atom in the substance is alike in composition, size and weight. Compounds.-When two or more elements unite chem- ically they form a compound. Iron, when it is left in the damp air, rusts. In other words the iron combines with the oxygen in the air and forms a new substance to which we give the name iron oxid. Iron is a heavy metal with a metallic lustre and is attracted by a magnet. Oxygen is a colorless, odorless gas. Iron oxid is a red brittle substance which is not attracted by a magnet. A compound has been formed. Each element has lost its identifying features, the new substance is homogeneous and the iron and oxygen cannot be separated by any me- chanical means. A compound is a pure substance since the minutest part of it looks and acts like every other particle. The smallest unit of this substance is called a molecule. A molecule may also consist of one or more atoms of the same element. For example it is known that two atoms of oxygen form a molecule. A molecule is the smallest particle of a chemical substance which can exist in a free state. The elements in a compound are its constituents. An element which enters into chemical ELEMENTS, COMPOUNDS AND MIXTUBES 11 combination easily is said to be an active element while those which are not active are termed inert. When it is difficult to liberate elements from combination the com- pounds are stable compounds. Formula.-A formula is a convenient way to represent a molecule of a compound. It tells us what elements are included in the molecule as well as the number of atoms of each constituent. Symbols are used to denote the ele- ments and subnumerals to indicate the number of atoms. The formula for sodium chlorid or common salt is NaCl. It indicates that one atom of sodium and one atom of chlorin are chemically combined to form sodium chlorid. The formula for magnesium sulfate is MgSO4. It con- sists of one atom of magnesium, one atom of sulfur and four atoms of oxygen. When only one atom is pres- ent the subnumeral 1 is not used. When a numeral is used before the formula it indicates the number of mole- cules. 2NaCl means two molecules of sodium chlorid and in like manner 3MgSO4 is three molecules of mag- nesium sulfate. Mixture.-In a mixture each of the substances in the material retains its own properties. We may have a mixture of elements or a mixture of compounds or a mixture of elements and compounds. When iron and sulfur are put together in a mortar and finely ground we have a mixture of the elements, iron and sulfur. The mass is not homogeneous. Each ingredient retains its own identifying features and they may be separated by a simple means, either by using a magnet to attract the iron or by dissolving the sulfur in carbon disulfid, a substance in which sulfur is soluble. In the latter 12 APPLIED CHEMISTRY FOR NURSES case, when the iron and sulfur solution is poured on filter paper, the filter paper will retain the iron (the residue) and the filtrate (that which passes through the filter paper) will be carbon disulfid with sulfur dis- solved in it. The sulfur may be recovered by allowing the solution to stand in the air when the carbon disulfid will pass off in vapor (evaporation), leaving the sulfur. The ingredients in a mixture are its components, from a Latin word meaning "put with." It is possible, however, to change this mixture of iron and sulfur to a compound. When a quantity of this mixture is put in a hard glass test tube and held in the flame of a Bunsen burner, a definite change takes place. Shortly there will be a little glowing furnace in the test tube and this will remain when the test tube is withdrawn from the flame. Two forms of energy are present, heat and light. The answer as to where they come from will be apparent later, but we will remember now that energy is involved in this change. Distinguishing Mixtures from Compounds.-In a com- pound the resulting properties from the chemical union, such as color, density, solubility, etc., are generally en- tirely different from those of the substances combined. In a mixture the resulting properties are the same as they were originally. In a compound every particle looks and acts like every other particle in the compound. In a mixture the particles of one substance differ from another. A compound always has a definite proportion of constitu- ents present, whereas a mixture does not. A compound may never be separated by purely mechanical means; mix- tures may be, as we saw in our experiment with the iron ELEMENTS, COMPOUNDS AND MIXTURES 13 and sulfur. In making a compound there are always energy changes involved as well as matter changes. In making a mixture there are no changes in energy. Standards for Comparison.-In order to have some basis for computing the weight of atoms, hydrogen is taken as a standard and it is given a unit value of 1; oxygen has a unit value of 16; sodium has a unit value of 23; chlorin has a unit value of 35.5; mercury has a unit value of 200. These are known as atomic weights; thus the atomic weight of an element is a number which tells the weight of an atom of that element compared with the hydrogen atom with a unit value of 1. Whenever we see the symbol for an element we can associate with it a weight equivalent and this number will represent one atom of that element. It is, however, when elements unite together to form molecules that we make valuable use of atomic weight. When sodium (Na) unites with chlorin (Cl) it forms sodium chlorid (NaCl) or common salt. As we have noted above the atomic weight of Na is 23 and Cl 35.5 therefore, NaCl is 23 -|- 35.5 = 58.5. This number (58.5) therefore represents the weight of NaCl and is called the molecular weight. The molecular weight is the sum of all the atomic weights of a chemical substance. Sulphuric acid is composed of hydrogen, sul- fur and oxygen. Its formula is II2SO4. Its molecular weight is H2 S 04 2xi + 32 + 4x16 = 98 A molecule of oxygen gas has the formula O2; its molecular weight is 2x16 or 32. Thus we have for all chemical substances a number which we may use in calculating the 14 APPLIED CHEMISTRY FOR NURSES weight proportion by which it enters into chemical reac- tion. This number may be expressed in grams. We have noted that when sodium and chlorin unite to form sodium chlorid they unite in the ratio of 23 to 35.5. Wherever we find NaCI whether in nature or pre- pared in the laboratory it will always have this ratio of sodium to chlorin. In other words it has a very definite composition by weight. This is the law of definite pro- portions; all elements combine in definite proportions by weight to form compounds. Chemical Equation.-Since we have represented ele- ments by symbols, and molecules by formulas we are now able to represent what takes place in a chemical reaction by an equation. It not only shows us the matter changes, but from it can be calculated the proportions by weight of the reacting substances. When two molecules of hydrochloric acid react with one molecule of zinc there is formed one molecule of hydro- gen and one molecule of zinc chlorid. The equation for this is 2HC1 + Zn = H2 + ZnCl2 The atomic weights involved in this equation are: hydrogen = 1, Cl = 35.5, Zn = 65 2HC1 + Zn -> H2 + Zn Cl2 1 65 1 65 35.5 35.5 2 2 36.5 2 71 2 71 73 + 65 = 2 + 136 138 = 138 ELEMENTS, COMPOUNDS AND MIXTURES 15 It will be observed from the above calculation that the molecular weight of HC1 is 36.5, Zn is 65, H2 is 2, and ZnCl2 is 136. The 2 before the HC1 indicates that two molecules of hydrochloric acid are necessary for the reac- tion and therefore the molecular weight of HC1 is multi- plied by 2. After having obtained the molecular weights it will be observed that 7 3 parts of hydrochloric acid react with 65 parts of zinc to form 2 parts of hydrogen and 136 parts of zinc chlorid and that the sum of the weights on one side is equal to the sum of the weights on the other. There are also the same number of atoms of each element on each side of the equation, 2 H atoms, 2 Cl atoms and 1 zinc atom. These two principles are true for all chem- ical equations: the number of atoms of each element on each side of the equation are equal; the sums of the molecular weights are equal. In like manner one molecule of mercuric chlorid re- acts with two molecules of potassium iodid to form one molecule of mercuric iodid and two molecules of potas- sium chlorid, HgCl2 + 2KI = Hgl2 4- 2KC1 The atomic weights involved in this equation are: Hg = 200, Cl = 35.5, K = 39, I = 127 Hg Cl2 +2K I = Hg I2 4- 2 K Cl 35.5 39 127 127 39 35.5 2 2 2 2 2 2 200 71 78 254 200 254 78 71 271 4- 332 = 454 4- 149 603 = 603 The above discussion leads to another important law in chemistry, the law of the conservation of matter which 16 APPLIED CHEMISTRY FOR NURSES states that matter is neither created nor destroyed, in- creased nor decreased in weight, when it undergoes chem- ical change. If we heat a piece of copper in the air we no longer have a bright red substance but we will find it coated with a black powder. If we weigh the copper before and after burning we shall find that it weighs more afterwards, since it has combined with oxygen in the air and this oxygen has weight. Both some oxygen and some copper have been transformed but there is still just as much oxygen and copper in the world as before. In a similar way when hydrochloric acid reacted with zinc two entirely different substances were formed yet the weight of the hydrochloric acid and zinc was equal to the weight of the hydrogen and the zinc chlorid; matter was neither created nor destroyed. The theory on which these fundamental laws are based was first advanced by an English chemist, John Dalton. To recapitulate we find there are five assumptions : 1. Elements are all divided into minute particles which we call atoms. 2. Atoms of the same element always have the same weight whether free or in combination. 3. Atoms of different elements have different weights. 4. The combining power of the atom is always the same under the same conditions. 5. Atoms go into combination in whole units. Valence.-We note that in compounds like, HC1 (hy- drogen chlorid), NaCl (sodium chlorid) ZnCl2 (zinc chlorid), A1C13 (aluminum chlorid), H2S (hydrogen sulfid), FeS (ferrous sulfid), HgCl (mercurous chlorid or calomel), HgCl2 (bichlorid of mercury), H2O (water), ELEMENTS, COMPOUNDS AND MIXTURES 17 CaO (lime or calcium oxid), KI (potassium iodid), Hgl2 (mercuric iodid), that different elements and also the same elements combine in different ratios to form compounds. One atom of hydrogen combines with one atom of chlorin but one atom of aluminum combines with three atoms of chlorin. One atom of mercury com- bines with one atom of chlorin to form one compound and with two atoms of chlorin to form an entirely differ- ent compound. This combining value of different atoms is known as their valence. Elements like H, Na, Cl, and many others which never unite with more than one other atom have a valence of one, and are called univalent. The valency of elements, having a greater valence is de- termined by the number of univalent atoms with which they combine or which they replace in a compound. Thus zinc combining with two chlorin atoms has a valence of two, aluminum combining with three chlorin atoms has a valence of three, oxygen combining with two hydrogens has a valence of two. Mercury in IlgCl has a valence of one and in HgCl2 a valence of two. This change of valence is common to many of the elements. In many compounds we have a group of two or more elements which behave in many chemical reactions as a unit or exactly as an element would behave. These groups or units are called radicals. The more common of these are the nitrate radical, No3, the sulfate radical, SO4, the hydroxyl radical, OH, the phosphate radical, PO4, the car- bonate radical, CO3, the bicarbonate radical, HCO3, and the ammonium radical, NH4. There are many others. These radicals have a valence exactly as do elements and it is determined in the same manner. The formula for 18 APPLIED CHEMISTRY FOR NURSES phosphoric acid is H3PO4 which tells us that the valence of the PO4 radical is three as it combines with three H atoms. H2SO4 is sulfuric acid and the SO4 radical has a valence of two. NH4C1 is ammonium chlorid and the ammonium radical has a valence of one. It is valuable to know the valences of elements and radicals as it is a great aid to writing the formulas of any compounds. For example, the valence of calcium is two and chlorin one. One may now write the formula for calcium chlorid as CaCl2. Knowing that the valence of iron may be either two or three we could easily derive the formulas for the two chlorids of iron, FeCl2 (ferrous chlorid and FeCl3 (ferric chlorid). The valence of the ammonium radical (NH4) is one, the valence of the carbonate radical is two. The formula for ammonium carbonate is then (NH4)2CO3 or two ammonium radi- cals combine with one carbonate radical. A parenthesis is used to enclose the radical when we wish to designate more than one to show that all the elements in the radical are multiplied. Types of Chemical Changes.-We found that com- pounds are substances which have been formed by the chemical union of two or more elements. Likewise these compounds may be separated again by a powerful force into the elements which compose them or one compound may react with another compound and form two new compounds, or a compound may react with an element. Let us see the various types of chemical changes which are possible. These chemical changes are termed reactions. Direct Combination. When sulfur burns in the air, it combines with the oxygen to form a new compound, ELEMENTS, COMPOUNDS AND MIXTURES 19 sulfur dioxid, SO2. This is an example of direct com- bination which is a chemical union whereby two elements unite to form one compound. Sulfur 4" Oxygen -> Sulfur dioxid S O2 SO2 Decomposition. Take a small quantity of red oxid of mercury in a test tube and heat it. Drops of mercury may be seen in the test tube and when a glowing splinter is thrust into the tube it bursts into flame, showing the presence of oxygen. In a decomposition, we begin with one substance and as the result of the chemical change we have two or more substances: Mercuric Oxid -* Mercury -j- Oxygen 2 HgO 2 Hg O2 Double Decomposition. The prophylactic treatment for the eyes of the newborn is to instill into the eyes a drop of 2% silver nitrate solution, AgNO3. The silver nitrate is then neutralized by saline solution, in other words, a solution of sodium chlorid, NaCl. These are both classed chemically as salts and when they enter into chemical combination they both decompose and reunite in a new combination. We no longer have silver nitrate and sodium chlorid but two new compounds have been formed, silver chlorid, AgCl, a white precipitate, which is insoluble in water, and sodium nitrate, NaNO3, which remains in solution. Silver nitrate-f-Sodium chlorid-> Sodium nitrate-|-Silver chlorid AgNO, + NaCl NaNO3 + AgCl Displacement. An element may displace another ele- ment in a compound, setting it free, and unite itself with 20 APPLIED CHEMISTRY FOR NURSES the remaining constituents of the compound. This is known as displacement. If you should attempt to clean any iron utensil with a solution of hydrochloric acid the gas hydrogen would be released from the hydrochloric acid, which is a compound of hydrogen and chlorin, the iron would take its place, and the resulting compound would be iron chlorid: Hydrochloric Acid + Iron -» Hydrogen + Iron Chlorid 2 HC1 + Fe H2 + FeCl2 Any compound that ends in "id" is a compound of two elements only. Energy.-Thus far we have only considered the matter change which takes place in a chemical change. When we changed our mixture of iron and sulfur into a com- pound of iron and sulfur or iron sulfid, heat and light were evolved, which continued to be evident after the test tube containing the material was removed from the flame. Where did the heat and light come from ? This leads us to consider the energy changes concerned in chemical changes. Energy is the ability to do work. There are various kinds of energy, heat, light, electricity, mechanical energy and chemical energy. We are all familiar with the first four and we know from practical experience that one may be converted into another. Elec- tricity may be transformed into heat or light. We see this every day. When coal is burned in an engine the heat changes water to steam, the steam expands and moves the piston and the engine moves. Heat has been trans- formed to mechanical energy. Where did this heat come from? We now have another law to consider, the Law ELEMENTS, COMPOUNDS AND MIXTURES 21 of the Conservation of Energy. Energy can neither be created nor destroyed but it may be transformed. When energy seems to be produced in any chemical action it has only been changed from some hidden to a visible form, and a definite amount of one kind of energy will pro- duce a definite amount of another. Chemical Energy.-It is believed that every substance contains a form of energy known as chemical energy and this energy does not become evident until the substance undergoes chemical change. All elements when free have more chemical energy than when in combination, and therefore when elements go into combination some of the chemical energy must be transformed to another form of energy, usually heat. When we wish to decompose a compound we must supply some form of energy since when the elements united to form that compound some chemical energy was transformed. We must give back that energy since elements when free have more chem- ical energy than when chemically combined. We usually give back that energy in the form of heat or electricity. We burn coal because it contains chemical energy which, when the coal undergoes a chemical change, that is, when it is burned, is transformed into heat and light. It is the chemical energy in coal which makes it valuable. When chemical changes take place in our bodies energy is liberated in the form of heat and mechanical energy. Huxley, the scientist, tells us that the living body must have fuel from which heat may be liberated. He says: "The living body is a machine by which energy is trans- formed in the same sense as the steam engine is, so all its movements are to be accounted for by the energy which 22 APPLIED CHEMISTRY FOR NURSES is supplied to it." The fuel is our food and we shall find that when it is burned in our bodies a definite amount of heat is liberated. When the body is at absolute rest and burning its own tissues the heat production is very con- stant for that individual. This fact is made use of, as we shall see later, in the determination of basal metab- olic rate. Measurement of Heat. In considering heat there are two factors, the intensity of heat, or the temperature, and the capacity for heat, or the quantity of heat. The tem- perature is taken by means of a thermometer, which registers the intensity of heat in the specified degrees of the Fahrenheit, Centigrade or Reaumur scales. The quantity of heat which is produced is measured by the calorie which is the amount of heat necessary to raise 1 gram of water one degree Centigrade. The large Calorie is the amount of heat necessary to raise 1 kilogram of water one degree Centigrade. Calorimeter. The calorimeter is an instrument for measuring the quantity of heat evolved in a chemical change. When 4 grams of Hydrogen and 32 grams Oxy- gen unite to form water, 138,000 calories of heat are set free. 2 H2 + O2 2 H2O + 138,000 calories When one molecular weight of water is formed 69,000 calories of heat are set free. An equation which shows the heat involved as well as the matter change in a chemical reaction, is a thermo-chemical equation. ELEMENTS, COMPOUNDS AND MIXTURES 23 Outline for Study I. Elements a. Defined b. In the body c. In frequent use d. Symbols e. Atom defined II. Compound a. Defined b. Its Characteristics c. Definitions (1) Active element (2) Inert element (3) Constituent (4) Stable compound d. Formula and what it represents III. Mixtures a. Their nature b. Means of separating c. Definitions (1) Filtrate (2) Residue (3) Evaporation (4) Component d. Distinguishing mixtures from compounds IV. Standards for Comparison a. Atomic weight b. Molecular weight c. Law of definite proportions V. The Chemical Equation a. Its significance b. Types of chemical change 24 APPLIED CHEMISTRY FOR NURSES (1) Direct combination (2) Decomposition (3) Double decomposition (4) Displacement c. Law of conservation of matter d. Valence VI. Energy a. Defined b. Law of conservation of energy c. Chemical energy d. Transformation of energy e. Measurement of heat (1) Intensity of heat (2) Capacity for heat (3) Calorie defined (4) Thermo-chemical equation CHAPTER III Oxygen and Oxidation Occurrence and Preparation.-One-fifth of the volume of the air is oxygen, 47% by weight of the crust of the earth is oxygen, 89% of water is oxygen, and it is an im- portant constituent in many organic and inorganic com- pounds. The human body has 72% of oxygen, so that we have more oxygen in the body than all other elements put together, and all living matter must have oxygen to carry on its life activities. Since many of the reactions in which we are interested involve the oxygen in the air, let us consider the com- position of air. Air is a mixture containing oxygen 21%, carbon dioxid 0.04%, nitrogen 78%, slight traces of argon and other gases, and water vapor. The quantity of water vapor varies with the temperature. For com- mercial use oxygen is obtained from the air or from water. Air is liquefied by changing its temperature and pressure. The carbon dioxid is first liquefied and is precipitated. Then the nitrogen and oxygen are separated by distilla- tion. The nitrogen vaporizes more quickly than the oxy- gen, so that it is distilled off first and the oxygen remains. In obtaining oxygen from water the electric current is used to decompose the water into hydrogen and oxygen. However, in the laboratory, if we wish to obtain small 25 26 APPLIED CHEMISTRY FOR NURSES quantities of oxygen for observing its physical and chem- ical properties, we use some substance which contains a quantity of oxygen which it is willing to give up. For instance, potassium chlorate, contains potassium, chlorin and oxygen and the formula (KC103) shows that there are 3 atoms of oxygen. We learned that chemical change is always accompanied by a change in energy and that elements when free have more chemical energy than when in combination. The potassium chlorate has chemical energy but it has not as much as the elements that com- pose it had when they were free. To obtain our oxygen we must supply energy and we do this in the form of heat. The potassium chlorate is heated and this reaction takes place: Potassium Chlorate -> Potassium Chlorid + Oxygen 2KC1O3 -> 2 KC1 + 3 O2 This is an example of decomposition. We may use other substances as for instance manganese dioxid (MnO2) or hydrogen peroxid (H2O2). When oxygen is obtained by heating potassium chlorate it requires considerable energy to have this decomposi- tion take place. However, if a mixture of potassium chlorate and manganese dioxid is used, a singular phe- nomenon occurs. The oxygen is liberated from the potassium chlorate much more quickly than in the previous case and the manganese dioxid remains unchanged. We may prove this by weighing the amount of manganese dioxid used and after the experiment is completed, filter- ing the material and weighing the residue which is manganese dioxid. There is no loss in weight. The man- OXYGEN AND OXIDATION 27 ganese dioxid has hastened the chemical action bnt it has not been changed. It has acted as a catalytic agent. A catalytic agent is a substance that will hasten a chemical change but is not changed itself. There are chemical sub- stances produced by the cells of the body called enzymes whose function it is to bring about chemical changes in the body while they themselves are not changed. Physical Properties.-If we examine the substance which we have obtained we find that it is a gas at ordinary temperature, that it is colorless, odorless and tasteless. It is heavier than water and is slightly soluble in water. Water has dissolved in it some free oxygen and all forms of aquatic life depend on this dissolved oxygen for their oxygen supply. It is also an important factor in the purification of water supplies. Gases are generally more soluble in cold water than in warm and when a glass of water is left standing in a warm room the bubbles of gas may be seen collecting on the sides of the glass. It is the loss of the oxygen and other gases which gives the flat taste to boiled water. The taste may be restored by passing the fluid from one vessel to another, thus "aerat- ing" it. When the water has been boiled to destroy patho- genic bacteria, care must be taken not to use utensils for aerating that have been washed in the contaminated water. Chemical Characteristics.-Oxygen will not burn itself but it will allow substances to burn in it; in other words, oxygen will support combustion or burning. Oxygen does not readily react with many substances at ordinary tem- perature but as the temperature increases the activity of oxygen increases and it will combine readily with the various metals and organic matter. Sodium and potassium 28 APPLIED CHEMISTRY FOR NURSES are readily oxidized at ordinary temperature, iron, zinc, tin, slowly rust in moist air, copper and lead oxidize when heated, while silver, gold and platinum are not affected by air. Platinum is used for transfer needles in bacteriology since platinum may be heated to a high temperature and yet not combine with the oxygen of the air. The reason why iron utensils are enameled is to protect them from the oxygen and moisture of the air. Surgical instru- ments are nickel-plated because nickel has a high melting point and it does not readily unite with oxygen. How- ever, if the nickel plate is worn and wet instruments are allowed to stand in the air they rust very readily. Oxidation.-This uniting of substances with oxygen is called oxidation. Whenever oxidation occurs heat is lib- erated. When iron rusts or oxidizes slowly in the air, we are not aware of the heat that is produced, but a piece of iron may oxidize so rapidly that we can feel the heat. Whether the oxidation takes place slowly or rapidly the same amount of heat is produced from a given propor- tion of iron and oxygen. If an element is oxidized the resulting product is an oxid, for example, zinc oxid, car- bon monoxid, carbon dioxid, sulfur dioxid, sulfur trioxid. When more than one combination of the same elements are possible subnumerals are used to denote the number of atoms of oxygen which are combined; e.g. SO2, sulfur dioxid, SO3, sulfur trioxid. These differ- ent combinations of sulfur and oxygen may seem at first contrary to the law of definite proportions, but note that sulfur dioxid and sulfur trioxid are two dis- tinctly different compounds with different properties. In sulfur trioxid wherever you find it the ratio of sulfur OXYGEN AND OXIDATION 29 to oxygen is always 32:48. Many examples will occur where there are two or more combinations of two or more elements, but always note that each compound is a dis- tinct entity with characteristic properties and must al- ways be considered as an entirely separate compound. Combustion. The term combustion is used in the ordi- nary sense to signify the combination of a substance with oxygen so rapidly that heat and light are evident. It is not necessary to have oxygen in order to have two sub- stances unite so rapidly that heat and light are apparent. When antimony and chlorin are brought in contact heat and light are liberated. However, when the burning takes place in the air, oxygen is involved. There are three es- sentials for combustion: 1. Two elements that have an affinity for each other; 2. In contact with each other; 3. Kindling temperature or ignition point. We may de- fine kindling temperature as that temperature at which two substances will combine in the burning act; it is also called the ignition point. Kindling temperature is spe- cific for different pairs of substances. We may illustrate this by a grate fire. Paper and oxygen will combine at a comparatively low temperature. Paper is therefore put on the bottom of the grate and with a lighted match we supply the kindling temperature at which paper and oxy- gen will unite. The heat from the burning paper will furnish the higher temperature at which the wood and oxygen will combine, and they in turn will give sufficient increase in temperature for the coal and oxygen to com- bine. Another fact that we must consider is that the greater the surface of contact with oxygen the lower the kindling temperature. For this reason -we do not pile 30 APPLIED CHEMISTRY FOR NURSES the wood closely together but first use fine shavings and then small pieces of wood rather than one large log. More of the wood is thus in contact with oxygen. Or we open the draft and allow more oxygen to get in and thus in- crease the surface of contact. If we take a burning candle, the flame of which has almost died out, and place it in a bottle of pure oxygen, it will burn brilliantly. We have increased the surface of contact. When we smother a fire with a blanket, we cut off the supply of oxygen, or when a fire extinguisher is used, the chemical involved is one that is heavier than oxygen and will therefore prevent the supply of oxygen from reaching the burning mate- rial. Spontaneous Combustion. Linseed oil is readily oxi- dized and for this reason is used by painters to furnish a firm, hard surface for paint. The painter may throw his oily waste into an attic or closet and shut the door. As the linseed oil oxidizes heat is produced which cannot escape and there is consequently an increase of tempera- ture until the kindling temperature is reached at which linseed oil and oxygen combine in the burning act. All three essentials for combustion are present and therefore heat and light are liberated. Oxidizing Agents.-Oxygen oxidizes organic matter to carbon dioxid and water. This is important in sewage disposal. If untreated sewage is dumped in large quan- tities into a body of water it will take up so much oxygen from the water that fish are unable to survive. It is therefore very desirable to thoroughly aerate sewage before it is turned into a stream in order to oxidize much of the organic matter. It also has the advantage of giving the OXYGEN AND OXIDATION 31 aerobic bacteria a better environment in which to do their work and purify the sewage. In the broad irrigation method, the intermittent and trickling filters, and activated sludge tanks for the purification of sewage the bacterial action depends upon the presence of oxygen. The relation of free oxygen to bacteria and the use of oxidizing agents as disinfectants is a matter of great importance. Aerobic bacteria thrive on free oxygen. A wound that is infected with anaerobic bacteria, such as the tetanus bacilli, is kept open in order that the oxygen from the air may reach the bacteria, since these organisms will not live in free oxygen. Oxygen need not be in its free state for oxidation. A substance which gives up its oxygen readily is known as an oxidizing agent. Many of the disinfectants are oxi- dizing agents. Potassium permanganate (KMnO4) is one which is frequently used for its germicidal and de- odorizing value, because is liberates oxygen when in con- tact w'ith organic matter. It is also used as the first aid treatment for alkaloid poisoning (morphin, strychnin, quinin, etc.), because it liberates oxygen which oxidizes the alkaloid, in other words burns it. Its stains are re- moved by oxalic acid. Potassium permanganate is re- duced by the oxalic acid and the resulting products are colorless. When we take oxygen away from any substance it is known as a reduction and the substance which at- tracts the oxygen is the reducing agent. Oxidation is always accompanied by reduction. Many bleaching agents owe their bleaching property to the fact that they release oxygen which oxidizes the pigment to a colorless com- pound. 32 APPLIED CHEMISTRY FOR NURSES Adrenalin, or Epinephrin may be oxidized either by free atmospheric oxygen or by oxidizing agents. It does not make any difference whether we allow a solu- tion of adrenalin to be exposed to the air or whether it comes in contact with oxidizing agents such as potassium permanganate, or hydrogen peroxid, the same chemical change takes place. It becomes pink in color and grad- ually turns brown, an indication that it is no longer fit for use. In sterilizing Adrenalin, it should be sterilized as needed. The necessary amount should be put in a test tube which is plugged with cotton to prevent air from get- ting in. The tube may then be placed in a container of boiling water and allowed to remain for half an hour. We have used the term oxidation and reduction only in relation to oxygen or its compounds. We may now broaden our definition of oxidation and include changes where oxygen is not directly involved. Any increase in the valence of an element is an oxidation and likewise a decrease of the valence is a reduction. By suitable re- agents we may change the medicinal calomel (HgCl) to the poisonous bichlorid of mercury (HgCL). We have increased the valence of the mercury and the reaction is one of oxidation. Oxygen in the Body.-Oxygen is found free and in combination in the body. All living matter must have oxygen, either free or in compounds. It is necessary for the body to have oxygen in order to provide energy in the form of heat and mechanical energy. Animals obtain it from the free oxygen in the air. When in the act of respiration oxygen is taken into the lungs, it diffuses through the capillaries and attaches itself to the hemo- OXYGEN AND OXIDATION 33 globin. A small portion of the oxygen also remains free. When the oxyhemoglobin reaches the cells oxidation takes place. The oxidation process is hastened by the action of enzymes called oxidases. In the cell the oxygen unites with the carbon and hydrogen obtained from our food. Exactly the same thing takes place as if we burned carbon and hydrogen in the laboratory. A matter change and an energy change takes place. Carbon dioxid and water are produced and heat is liberated. In this way the body maintains its heat. The blood receives in exchange for its oxygen, carbon dioxid and water. The carbon dioxid is excreted by the lungs and the water is eliminated by the lungs, kidneys, intestines and skin. Nature has provided a wonderfully efficient means for providing the body with sufficient oxygen in a compara- tively short time. When we consider that the surface area of the alveoli of the lungs is about 90 square yards and that one cubic millimeter of blood contains between four and five million red blood cells, it will be seen that the surface of contact with oxygen is very great. Other substances besides carbon and hydrogen are oxidized in the body and it is possible that other oxygen in addition to that obtained through the lungs may be involved in the oxidation processes of the body. We find that as we raise the temperature, oxidation goes on more rapidly. This is true in our bodies. As the tem- perature of the body rises, as in febrile conditions, oxida- tion goes on more rapidly. In health the heat regulating apparatus of the body maintains the temperature at 98.6° F. Extra heat is lost by radiation and by evaporation of water from the skin. 34 APPLIED CHEMISTRY FOR NURSES Oxygen as a Stimulant.-When the cells do not receive their normal supply of oxygen, due to congestion in the lungs or the inability of the heart to pump the blood fast enough and in sufficient volume to bring the oxygen to the cells, the condition known as cyanosis results, char- acterized by a bluish tinge of the skin, especially around the lips and nails. The cyanosis may become very severe and "oxygen" may be ordered. Every hospital ward has a tank of oxygen for emergency use. The oxygen is kept under pressure and when the pressure is reduced it allows the oxygen to escape. In administering oxygen in this way we are helping the patient to get it more easily and more quickly than he would by breathing the air. In other words, the surface of oxygen is increased. Oxygen is also used as an antidote for carbon monoxid poisoning and illuminating gas poisoning. In administering oxygen from an oxygen tank, the gas is passed through water in order to moisten it and by observing the bubbling of the gas in the water the flow of gas may be regulated. The funnel should be held at the side of the patient's face, slightly above the nose and tilted slightly forward. It will be remembered that pure oxygen is heavier than air and that if the funnel is held below the nose the patient will not breathe the oxygen. Ozone.-A single atom of a gas may not exist alone, so that we find always two atoms of oxygen going together. We may think of the atoms of oxygen in the air as in pairs. When an electric spark passes through oxygen, some of the pairs split apart and the atoms unite with other pairs so that there are groups of three. This is known as Ozone, O3. Ozone is formed in the air when an electric OXYGEN AND OXIDATION 35 spark passes through it, as for instance when lightning flashes or when electric sparks pass between terminals. It is also formed by the extremely slow oxidation of organic matter. Ozone is very unstable and the tendency is for the extra atoms to fall apart and unite, giving oxygen again. Ozone is very active and is a better oxidizer than oxygen. It is used for the quick purification of water by oxidation. The matter present in oxygen and ozone is the same. Those elements which are alike in matter con- tent but have a different grouping of the atoms and there- fore different characteristics are called allotropic forms of the element. Outline for Study I. Oxygen a. Meaning of word b. Occurrence and preparation (1) Composition of air (2) Liquefying air (3) Preparation in laboratory c. Catalytic agents (1) Definition (2) In body d. Physical characteristics of oxygen (1) Solubility in water (2) Aerating water e. Chemical characteristics (1) Activity (2) Action with metals (3) Oxidation (4) Oxids (5) Combustion 36 APPLIED CHEMISTRY FOR NURSES (6) Essentials for combustion (7) Increasing surface of contact II. Oxidizing Agents a. Defined b. Reduction c. Practical applications III. Oxygen in the Body a. Necessity b. Oxyhemoglobin c. Oxidation in cell d. Matter and Energy changes IV. Oxygen as a Stimulant a. Indication for its use b. Method of administration V. Ozone a. Allotropic forms of oxygen b. Uses of ozone CHAPTER IV Hydrogen The word "hydrogen" means "water former" and the name was given to this element because it was found to be a constituent of water. It is a constituent of water but it is also an important constituent in acids. If the elements, to which the names oxygen and hydrogen were given originally, were being named in the light of present day knowledge the names might be reversed. Supply of Hydrogen.-Minute traces of hydrogen are found free in the air. We find it in chemical combination with oxygen in water, and with other elements in acids, bases and organic substances. It is prepared by electroly- sis of water, but small amounts of hydrogen in the labora- tory may be obtained by the action of a metal on a dilute acid. Physical Properties.-Hydrogen is a colorless, odorless, tasteless gas, slightly soluble in water. It is lighter than air, in fact it is the lightest gas known and therefore it is used for balloons. Chemical Behavior.-Hydrogen unites readily at an elevated temperature with oxygen, chlorin, sulfur and nitrogen. . It burns with a colorless flame. It may be freed from water and acids by the action of certain metals. The chemists have been able to arrange a list of metals 37 38 APPLIED CHEMISTRY FOR NURSES in the order of their activity in freeing hydrogen from water and acids. The position of a metal in this list is important, because not only do these metals, which are above hydrogen in activity, displace hydrogen from acids and from water, but it also indicates their activity in com- bining with oxygen; those above hydrogen in the list com- bine readily with oxygen, and are the metals which are always found in combination in nature. The metals be- low hydrogen may be found free. This list is known as the electro-chemical series and we shall have occasion to refer to it again. The list as printed is incomplete and only includes the more common elements. Potassium Sodium Lithium Calcium Magnesium Aluminum Manganese Zinc Chromium Cadmium Iron Nickel Tin Lead Hydrogen Copper Antimony HYDROGEN 39 Bismuth Mercury Silver Platinum Gold Metals above hydrogen in activity will react with water to give free hydrogen and a base or oxid. Those which react at a low temperature, such as sodium, potas- sium, calcium, give an hydroxid. If we test water with red litmus paper there is no action, but if we put a small piece of sodium in the water and then test it we will find that the litmus paper turns blue and that the solu- tion which we have has a slippery feeling. It is sodium hydroxid: 2H OH + 2Na H2 + 2NaOH Water Sodium -» Hydrogen -f- Sodium Hydroxid This is an example of chemical displacement. It will be noted that only part of the hydrogen in the water has been displaced. Sodium and potassium react with such vio- lence with water, that great care must be used in handling them. They may never be handled with the fingers since the moisture on the hands will react with them and severe burns result. Aluminum will displace hydrogen from water at 100 ° C., the boiling point of water, but it does it so slowly that it is not noticeable. However, it accounts for the thinning of aluminum pans. Most of the cooking utensils are not pure aluminum. The metals that react at a high tem- perature, such as iron, would give an oxid: 40 APPLIED CHEMISTRY FOR NURSES Water -f- Iron -> Hydrogen + Iron Oxid 3H0H 4- 2Fe -» 3H2 + Fe2O3 The temperature at which iron will react with water is so high that we do not have to consider this in making pipes, but it will be noted that boilers which are subjected to very great heat are made of copper. The metals above hydrogen in activity will react with an acid to form a salt and free hydrogen. For this reason an acid must never be poured down a sink into the pipes in the laboratory until it has been diluted very greatly. 2HC1 + Zn H2 + Zn Cl2 Hydrochloric Acid + Zinc -» Hydrogen + Zinc Chlorid Some metals such as aluminum, zinc and tin will dis- place hydrogen from potassium hydroxid and sodium hydroxid. Hydrogen is used as a reducing agent. If copper oxid is allowed to come into contact with hydrogen the latter will unite with the oxygen to form water and free copper will remain. There is a process by which hydrogen is united to cot- ton seed or similar oils in the presence of a catalytic agent. This is called hydrogenation and raises the melting point of the oil so that it becomes solid at ordinary temperatures. Crisco is an example of an hydrogenated oil. Oxids of Hydrogen.-There are two very important oxids of hydrogen, water and hydrogen peroxid. Water will be discussed more fully later. Hydrogen Peroxid.-This is a compound of hydrogen and oxygen with the formula H2O2. It is a syrupy, color- HYDROGEN 41 less liquid with a characteristic odor and taste. What we use is a very dilute solution which contains about 3% of hydrogen peroxid. Chemical Action.-Hydrogen peroxid is very unstable and it readily gives up its excess of oxygen in the pres- ence of heat, organic matter or catalysts. Manganese dioxid acts as a catalytic agent in contact with hydrogen peroxid. When hydrogen peroxid is put on the skin, there is no action, but if the skin is broken it immediately effervesces. Effervescence is the bubbling of a gas gener- ated in a liquid. This action of hydrogen peroxid when it is in contact with the tissues would indicate the presence of an organic catalytic agent. The saliva also contains an enzyme or a catalase which causes the oxygen to be set free in the mouth. It is used as a mouth wash or gargle. The presence in the body of these catalytic agents which act on hydrogen peroxid, has led to the hypothesis that during the oxidation processes in the body, hydrogen peroxid is formed and these catalytic agents decompose it immediately to water and oxygen. Hydrogen peroxid was formerly used very generally as an antiseptic. Because of its instability, it is believed now that its chief value is in its mechanical action, since the freeing of the oxygen will dislodge pus and other debris from a wound. It must be used with great care in a deep wound, since it may free the oxygen so rapidly and with such force that the tissues may be injured. Organic matter, such as silk, hair, feathers, and nails are bleached by hydrogen peroxid, because of its oxidizing power. For this reason, it is used to remove blood stains from linen. Because it decomposes readily with heat and 42 APPLIED CHEMISTRY FOR NURSES light it is extremely important that it should be kept in a cool place in a dark bottle. Outline for Study I. Hydrogen a. Meaning of word b. Supply c. Physical properties d. Chemical behavior e. Methods of obtaining (1) From water (2) From acids II. Hydrogen Peroxid a. Composition and formula b. Chemical action (1) Effect of catalytic agent (2) Catalase in body (3) Action in wounds CHAPTER V The Kinetic-Molecular Hypothesis. The Gas Laws We have noted in the preceding chapters that the nnit of a chemical substance is the molecule, therefore that all matter as it exists must be composed of molecules. We have also noted that all matter exists in three states, solid, liquid, and gaseous. Science has developed a convenient hypothesis to explain how these molecules exist in matter. A hypothesis to be valid must explain action under all conditions and the more laws that the hypothesis fits in with the more valid we assume it to be. The kinetic- molecular hypothesis is applicable to so many phenomena that it has become a permanent fixture in the field of sci- ence. It states: 1-All matter is composed of infinitely small particles called molecules. These molecules are separated from each other by spaces. 2-All molecules of the same chemical substance are alike. 3-All molecules are in perpetual motion, and move in straight lines. 4-All molecules are perfectly elastic. Take a rubber ball. It is elastic and when you drop it on the floor it will bounce back again, but never as high as it was dropped 43 44 APPLIED CHEMISTRY FOR NURSES from and finally it will become quiet on the floor. You can compare the elasticity of a molecule to the rubber ball with the exception that the molecule would bounce back as far as it was dropped and therefore will keep bounc- ing forever. It is perfectly elastic. In the gaseous state the spaces between the molecules are very great compared to the size of the molecules. This condition gives them much freedom of motion. There are always two forces at work on the molecule, cohesion which is the attraction that molecules have for each other and opposing this is the energy which the molecule has which keeps it in perpetual motion. In a gas, cohesion is at a minimum because the molecules are so far apart that they run rampant. If you look at a bottle of oxygen you will see nothing but if you allow your imagination free range you will see myriads of infinitely small particles travel- ing at a terrific pace, hitting each other and bouncing away with untiring energy and bombarding the sides of the container like corn in a corn popper. The composition of a gas in a container is the same in all portions. It will not settle to the bottom, because all molecules of the gas are the same and are in constant motion to all parts of the container. When we use the oxygen tank we do not have to tip the tank as we would a bottle of liquid since the molecules are in constant motion and the oxygen is released instantly the pressure is removed. When a patient is given ether it vaporizes immediately and quickly permeates to all portions of the room or when a stop cock of a gas range is left open the illuminating gas quickly diffuses with the air. Gases are readily diffusible THE KINETIC-MOLECULAR HYPOTHESIS 45 because the molecules of one gas are so far apart that the molecules of other gases may travel through it with little hindrance. Gases may be compressed to a small volume. Consider how large a container would be required to hold sufficient oxygen for a number of patients if we were unable to compress it. When the gas is compressed it exerts pres- sure as can be noted by the hissing sound when it escapes. Gases may be compressed because the molecules are far apart and we are able to shove them closer together. When we have driven many times as many molecules into a container as were there previously we have increased the bombardments on the inside of the container just that many times and of course these extra bombardments exert the force or pressure of the gas. We can now see the validity of Boyle's Law which states that the volume of a gas varies inversely as the pressure applied to it. If we have one liter of gas at 15 lbs. pressure per square inch and increase the pressure to 30 lbs. per square inch the volume of the gas will have decreased to one half liter. When we increase the temperature of the autoclave the pressure inside rises. In warm weather stoppers from ether bottles and hydrogen peroxid bottles blow out due to the gas which has collected. When the air inside an automobile tire is heated by the sun or by traveling it sometimes blows out. All these instances tell us that the pressure of a gas increases with the temperature. We can also explain this by the kinetic-molecular hypothesis. Heat is a form of energy and molecules like other engines convert heat into motion. When you heat a molecule it travels faster than before; thus when you heat a gas in a 46 APPLIED CHEMISTRY FOR NURSES container each molecule traveling faster than before will bombard the wall of the container many more times and thus exert additional force or pressure on the container. Charles' Law states that any gas increases or decreases ( of its volume for every degree centigrade increase or Z (o decrease in temperature. The greater the temperature of the gas the greater is its volume. In 1811 Avogadro, an Italian physicist, put forth the hypothesis that equal volumes of gases at the same tem- perature and pressure contain the same number of molecules. It is a logical deduction from the kinetic- molecular hypothesis and it is very workable in the field of chemistry. We can deduce directly from this hypoth- esis that the density of gases is in proportion to their molecular weight or that CO2 with a molecular weight of 44 is 22 times as heavy as H2 with a molecular weight of 2. We know also that one liter of hydrogen gas will combine with exactly one liter of chlorin gas to form hydrogen chlorid as both the liter of hydrogen and chlorin contain the same number of molecules. Liquids.-We find similar applications of the kinetic- molecular hypothesis to the liquid state as we have noted in the gaseous state. In the liquid state cohesion has over- come much of the activity of the molecules. Instead of finding them far apart we find them close together yet they have perpetual motion and there are spaces between all molecules. Two liquids will diffuse in the same man- ner as gases but not as rapidly. This is because the spaces between the molecules are much decreased and the mole- cules of one liquid get in the way of those of the other. THE KINETIC-MOLECULAR HYPOTHESIS 47 The higher the temperature the more rapid the diffusion because the molecules move faster. When we have a liquid in an open dish many of the molecules on reaching the surface of the liquid in their travels will continue out into the air above. This is evaporation. If we decrease the pressure of the air above the liquid by removing some of the molecules of oxygen and nitrogen we will find that evaporation will take place much more rapidly as on high mountains. If we increase the temperature of the liquid the speed of the molecules will be increased and many more will leave the surface of the liquid and evaporation will be increased. When the speed has become so great that the pressure of the molecules leaving is equal to the pressure of the gas above then wTe have the phenomenon of boiling. We can compress a liquid only to a very small degree. This is because the molecules are so close to- gether. Most liquids expand a small amount on heating, because the extra energy increases the interspaces between the molecules. Solids.-In solids cohesion has still further overcome the activity of the molecule until the substance will no longer seek the form of the container. The matter is still discrete and the molecules are in perpetual motion. That the molecules are still in motion may be shown by pressing certain different solid surfaces together and leaving for some time. It has been demonstrated that some of the molecules of one have diffused into the other. 48 APPLIED CHEMISTRY FOR NURSES Outline for Study I. Kinetic Molecular Hypothesis a. Its four assumptions b. Its application to gases (1) Cohesion (2) Compression of gases (3) Boyle's Law (4) Influence of increased temperature on pressure (5) Charles' Law (6) Avogadro's Theory c. Its application to liquids (1) Evaporation (2) Boiling d. Its application to solids (1) Influence of cohesion on the molecule CHAPTER VI Water Water is so common a substance and yet so vital to us all that perhaps a study of its chemistry will make us appreciate more its value, especially in our own work. It was not until after 1781 that the chemists knew that water is a compound. They found that water is a com- pound of hydrogen and oxygen, and by analysis, they de- termined the proportionate amount of each by volume and by weight. There are two volumes of hydrogen to one volume of oxygen, and its ratio by weight is one part by weight of hydrogen to eight parts by weight of oxygen. There is a profuse supply of water in the crusts of the earth, lakes, rivers, streams, in the atmosphere and in all plant and animal life; Every living cell contains water in varying amounts. The human body contains 68 per cent of water. The body can go a large number of days without food, but not without water. It is essential to have water for digestion, proper excretion, circulation, the regulation of the body's heat, and other vital functions, so that it is part of the nurse's responsibility in caring for her patients to be sure that they do not become dehydrated. One of the oldest methods of preserving food, that of drying, is based on the fact that bacteria and other micro- organisms which spoil food must have water in order to 49 50 APPLIED CHEMISTRY FOR NURSES grow. Drying out destroys many of the vegetative bac- teria. The importance of water in promoting health and its use in the household for cooking and cleaning makes it one of our most valuable chemical compounds. Physical Properties of Water.-Water is a colorless liquid at ordinary temperature. It is tasteless and odor- less. Its freezing point is 0° C. (32° F.). It will evapo- rate at all temperatures, but it evaporates more quickly at 100° C. (212° F.). The boiling point of water depends on the atmospheric pressure. On high mountains it is very hard to cook food because of the low atmospheric pressure and the consequent lowering of the boiling point. In the autoclave used for sterilization if the steam pressure is raised to 15 lbs. the temperature of the water and steam inside is increased about 20° C. (36° F.) above the boil- ing point of water. This increase of temperature makes the autoclave far more efficient than boiling water for sterilization. The pressure cooker is identical with the autoclave in principle and food is cooked in a much shorter time than in boiling water. Water reaches its greatest density at 4° C. (39.2° F.). As the temperature of water is lowered, it contracts until it reaches 4° C., when it begins to expand until it reaches zero, and changes to ice. When water is used as a standard it is taken at its greatest density, that is, the temperature of 4° C.; for example, the weight of 1 c.c. of water at 4° C. is one gram. Chemical Characteristics of Water.-Water does not decompose very readily. The fact that we have so much of it shows that it is a stable compound. There are metals, however, with which it is extremely active as we have al- ready noted. It will react with metallic oxids to form WATER 51 bases, and with non-metallic oxids to form acids. It will unite with certain salts to form hydrates. Still another reaction is that of hydrolysis whereby certain substances undergo a double decomposition with water. We shall discuss later these chemical reactions with water. Foreign Matter in Water.-Water may contain a great many impurities, either in solution or in suspension. A pure water supply is an important factor in maintaining good health in a community, and from the standpoint of the bacteriologist, water is divided into three classes: (1) Good water, which is relatively free from bacteria and other material which would affect health. (2) Pol- luted water, which indicates that there is dead and decay- ing matter present, and therefore there are putrefactive bacteria present. The effect on health will depend on the quantity present. (3) Infected water, which contains pathogenic micro-organisms. There are also in water min- eral substances, the type of which depends on the nature of the rocks and soil in the locality. The presence of these minerals determine whether the water is hard or soft water. While minerals in waters would have no effect on health, in fact the salts may have a beneficial effect, hard water is not economical for use in the house- hold or for use in steam boilers. The bacteriologist, in making his examination of water, plates a definite amount for his bacterial count, and then makes a pure culture of the organisms present. He bases part of his conclu- sions on the fact that certain bacteria will bring about definite chemical changes in the material which he uses as the media on which to grow them. The presence of B. Coli usually indicates pollution by sewage. To free 52 APPLIED CHEMISTRY FOR NURSES water from the impurities, which affect health various types of filters are used, or a chemical is added which acts as a disinfectant or as a precipitant. For purifying small quantities of water for drinking purposes or for a house- hold supply, boiling for ten minutes is satisfactory. For some processes, it is important that neither the mineral matter nor the organic material be present. Distilled water is necessary. This is prepared by boiling water and collecting the condensed steam. The mineral matter and most of the organic matter not being volatile will remain behind. Distilled water is used in the chemical laboratory, and in the drug store. If a solution of silver nitrate were made with ordinary tap water it would be cloudy, due to the formation of insoluble silver chlorid from the action of the silver with the chlorids most always present in tap water. It is also used in making intravenous solutions. For these it should be freshly prepared, as the presence of bacterial protein may possibly cause a "reaction" in the patient. Water as a Solvent.-A solution is a homogeneous dis- tribution of one substance throughout the mass of a liquid, so that it is lost to sight as an individual body. There are two parts to every solution, the solvent or the liquid used to dissolve, and the solute, which is the dissolved sub- stance, which may be a gas, a liquid or a solid. The factors which affect solubility are the nature of the solvent, the nature of the solute and the temperature. With gases pressure is a factor since an increase in pressure increases the weight of the gas going into solution. Water is the most common solvent, but oil, for example, will not dis- solve to any extent in water. It will dissolve in alcohol, WATER 53 and it is freely soluble in ether. lodin crystals dissolve in water only to a very small degree, yet they will dissolve freely in alcohol. Balsams and resins are also freely soluble in alcohol and in ether, but not in water. The dissolving of the substance is hastened by stirring or shaking the container. In the removal of stains the ques- tion of solubility has to be considered and while some sub- stances are removed by a chemical change taking place between the pigments and the chemical applied, others are removed by applying some material in which the staining substance is soluble. As a rule as the temperature is increased, substances become more soluble. However, gases are more soluble at a lower than a higher temperature, as we noted in con- nection with the oxygen in solution in water. When a solute and solvent are in contact at a given temperature and the solvent has dissolved all the solute which it is able it is said to be saturated and the solution is called a satu- rated solution. An unsaturated solution is one in which the solvent is capable of holding more solute in solution at a given temperature. In a supersaturated solution, the solvent is holding an excess of solute above saturation for that temperature. Under normal conditions, when the temperature is raised, the solvent will hold more solute. It is then a saturated solution for that temperature, but when the solution is cooled, the excess forms crystals, in the case of solids. There are a few substances, which, when saturated at a high temperature, may be cooled with such care that they retain all of the solute in solution. They are known as supersaturated solutions. We may test whether a solution is saturated or not by dropping in 54 APPLIED CHEMISTRY FOR NURSES a crystal of the substance. If the solution is unsaturated, the crystal will go into solution; if the crystal remains, it is a saturated solution. If it is supersaturated, all the excess above saturation at that temperature, will crystal- ize from the solution. Substances in solution have an effect upon the boiling or freezing point. The boiling point of a liquid is raised by dissolving a solid in it and the freezing point is lowered. Volatile substances, such as ether, chloroform and alcohol have a lower boiling point than water and are best kept in a low temperature since it will decrease their tendency to evaporate. Heat of Solution.-Heat may be absorbed or appear when substances are put into solution; for instance, camphor, if dissolved in alcohol becomes very cold be- cause the heat is absorbed. On the other hand, if sodium sulfate is dissolved heat appears. This is known as the heat of solution. Suspensions and Colloidal Solutions.-If a finely divided solid is put into a liquid, in which it is not soluble, particles of it are seen floating in the liquid, as in "chalk mixture." It is a suspension. Substances which are in suspension may be separated from the liquid by filtration. The filter paper is porous, thus allowing the liquid to go through. Colloidal solutions are intermediate between true solutions and suspensions. The substance is too coarsely divided to be a true solution and yet too fine to be called a suspension. They will not settle or pass through an animal membrane. For example, boiled starch and water is a colloidal solution. A colloidal solution may exist in a liquid form as egg albumen and barley water or WATER 55 in a jelly like form as gelatin, glue, barley jelly, and fruit pectin. Colloidal solutions as barley water or barley jelly, oatmeal water, and other starch diluents are used in infant feeding, since the addition of the colloidal solution to the milk prevents the formation of hard, large casein curds. Osmotic Pressure.-When a dried fruit with its skin intact is placed in water it will swell. The inside of the fruit contains sugar and the skin of the fruit is not per- meable to sugar but it is permeable to the water. A mem- brane of this nature which is permeable to one substance and not to another is called a semipermeable membrane. When the fruit is placed in the water the latter easily passes through the skin to the inside of the fruit and the molecules become dispersed among the sugar molecules so that it is unable to pass out of the skin again as fast it came in. Thus we have more water passing into the skin than we have passing out. This exerts a pressure within the skin and causes the fruit to swell. Any dried fruit like a piece of dried apple will swell when placed in water. This is because each cell wall acts as a semipermeable membrane and each cell taking in water causes the whole to enlarge. The roots of a plant in the ground absorb water from the soil. The thin bark on the roots acts as a semiper- meable membrane. It will readily allow water to pass through it, but on the contrary it will not allow the chemi- cal substances of the sap to pass out. When the water passes into the roots it is dispersed among the molecules of the chemical substances of the sap and there are fewer molecules of water to pass out through a given space on the 56 APPLIED CHEMISTRY FOR NURSES root than are coming in and thus the root is said to absorb water from the soil. When a red corpuscle is suspended in distilled water the cell wall membrane acts as a semipermeable membrane. It is readily permeable to water but many of the chemical substances inside of the cell are unable to pass out. Again the passage of water into the cell is greater than the pas- sage out and the cell swells until it ruptures. This process in red blood cells we call hemolysis. The intestinal wall is practically impermeable to certain substances while it is readily permeable to water. It thus acts as a semipermeable membrane. Magnesium sulfate is a substance to which the intestinal wall is practically impermeable. The water passes from the tissues into the intestine much faster than it leaves. This explains the copious, watery stools of magnesium sulfate catharsis. Phenomena similar to these are very common to animal and plant life. The process is known as osmosis and the pressure exerted is the osmotic pressure. Practically all animal or plant membranes are impermeable to colloidal solutions. This is important in biological processes be- cause all proteins are colloidal solutions. Outline for Study I. Water a. Composition. b. Supply c. Importance d. Physical and chemical properties (1) Boiling point (2) Action with metals WATER 57 II. Foreign Matter in Water a. Classification of water (1) Good water (2) Polluted water (3) Infected water b. Examination (1) Chemical (2) Bacteriological c. Distilled water III. Solutions a. Definitions b. Factors effecting solubility c. Practical applications d. Saturation e. Effect on boiling point and freezing point f. Heat of solution IV. Suspensions and Colloids a. Definitions b. Colloids in infant feeding V. Osmosis a. Osmotic pressure b. Practical applications CHAPTER VII Electrolysis. Ionization. Acids Electricity is a powerful force, which has become almost indispensable in our modern life. It may be conveyed from one point to another and the substance through which it passes is known as a conductor. There are good conduc- tors and poor conductors. The human body is a good con- ductor. If it comes into contact with a live wire the body receives a "shock." The first aid treatment is to get the body out of contact with the wire by using rubber gloves or a glass rod to remove it, since these are both poor conductors. Electricity is of two kinds, positive and negative and is represented by the signs + and -. Two bodies with positive electricity repel each other, or two with negative repel, but opposites have a strong attraction for each other. Electric batteries have two poles, a nega- tive pole or cathode, and a positive pole or anode. When a current flows through a wire we can conceive of positive charges flowing in one direction and negative charges flow- ing in the other direction tending to attract each other. If we try to use a piece of rock salt for a conductor we will find that it does not conduct electricity. If we im- merse wires from a negative and positive pole of a battery into water we will find that it will conduct practically no current. If we dissolve the salt in the water the solution 58 ELECTROLYSIS. IONIZATION. ACIDS 59 will then conduct electricity quite readily, in other words it has become a conductor. In making an electrocardio- graph the cloth which is placed over the artery is saturated with salt solution so it will conduct the current. Sub- stances which when dissolved in water will conduct an electric current are called electrolytes. The action that the current may have on the electrolyte is called electrol- ysis. Acids, bases and salts are electrolytes. In order to explain why a substance in solution conducts electricity it is convenient to assume that it breaks into two or more particles, carrying negative and positive charges of electricity. These charged particles are called ions. They are always atoms or radicals and carry the same number of charges as their valence. For example NaCl would ionize into Na ions and Cl ions, each carrying one charge of electricity as each has a valence of one. Na2SO4 would ionize into two Na ions with one charge each and SO4 ions with two charges as this radical has a valence of two. When we pass a current through an elec- trolyte the metallic elements migrate toward the negative pole and as like attracts unlike we assume that the metallic atom has the positive charge attached to it and by the same reasoning the acid atom or radical has the negative charge. Thus in NaCl the Na carries one positive charge and the Cl one negative charge and similarly in Na2SO4 the Na has two positive charges and the SO4 radical carries two negative charges. Ionization is important in chemistry for the reason that practically no chemical reactions take place at ordinary temperature in the absence of water. We have already mentioned that the boiling point and freezing point of a liquid is affected by dissolving a sub- 60 APPLIED CHEMISTRY FOR NURSES stance in it. With non-volatile, non-electrolytes the in- crease in boiling temperature is directly proportionate to the molecular concentration. For example : a liter of water boils at 100° C. A liter of water with 90 grams of glucose boils at 100.28°, a liter of water with 180 grams of glucose boils at 100.56°, while 360 grams of glucose in a liter of water boils at 101.12°. The same is true with regard to freezing temperature. The decrease is in direct proportion to the molecular concentration irre- spective of the substances provided they are non-volatile and non-electrolytes. With electrolytes in solution the depression of the freez- ing temperature and the increase of the boiling tempera- ture is abnormal as compared with the effect produced by non-volatile electrolytes and the reason for this is found in the ionization theory. When electrolytes are put into solution the molecules dissociate into ions and each ion has the same effect on boiling temperature or freezing temperature as a whole molecule. Acids.-All inorganic acids in solution have certain characteristics in common and these same characteristics to a less degree are shown by organic acids. Let us ex- amine the formulas of some common acids. H Cl Hydrochloric Acid HI Hydriodic Acid H NO3 Nitric Acid H2SO4 Sulfuric Acid H2CO3 Carbonic Acid H3BO3 Boric Acid H3PO4 Phosphoric Acid. ELECTROLYSIS. IONIZATION. ACIDS 61 From the above formulas, it will be noted that the one element that is common to all these acids is hydrogen. We stated before that acids in solution have certain char- acteristics in common. We are ready now to make the statement that the common properties of acids when they are dissolved in water are due to the presence of hydrogen ions. It may be noted also from the above formulas that the second element in all these acids is a non-metal; for example, chlorin, iodin, sulfur, carbon, boron, phosphorus. In addition some of these acids contain oxygen so that we are ready for another statement. Acids are com- posed of hydrogen, a non-metal and may or may not contain oxygen. The non-metal or the non-metal and oxygen is known as the acid radical. The acid radical is responsible for the specific properties of an acid. It is the factor which is responsible for the difference between boric acid and nitric acid. When an electric current is passed through a solution of acid the hydrogen ions are attracted to the negative pole, since the hydrogen ions have a positive charge and like repels like, and the acid radical ions are attracted to the positive pole. The acid radicals are known as nitrates, carbonates, sulphates, phosphates, etc., according to the acid of which they form a part, as for instance Nitric Acid II NO3 Hydrogen Nitrate Whenever a chemical change takes place between an acid and another substance the acid radical acts as one 62 APPLIED CHEMISTRY FOR NURSES although it may be composed of two elements, and the split takes place between the hydrogen and the acid radical. Common Properties of Acids.-1. All acids are sour. The various fruit juices are given to quench thirst as they stimulate the flow of saliva. 2. Action with Indicators. Litmus, a vegetable dye obtained from a lichen, is used as an indicator. Porous paper is saturated with the dye and affords a convenient means for using the indicator. Acids will turn blue litmus paper red. Other indicators which are used are phenol- phthalein and methyl orange. Phenolphthalein is color- less in the presence of acids and methyl orange becomes red. 3. Action with Metals. We have already referred to the fact that metals above hydrogen in activity, such as zinc, iron and lead will free hydrogen from dilute acids. It is a fact that instruments are sometimes put into car- bolic acid for disinfection, but carbolic acid is a very weak acid. Acids should never be poured down a pipe until they have been very much diluted. Vinegar and lemon juice stain steel knives because they contain organic acids. 4. Action with Bases. Acids react with bases to form water and a substance known as a salt. A base contains a metal and oxygen and hydrogen. In this compound the oxygen and hydrogen act as a unit which is known as the hydroxyl radical. The hydrogen from the acid unites with the hydroxid to form water while the metal of the base joins with the acid radical to form the salt. ELECTROLYSIS. IONIZATION. ACIDS 63 Acid + Base -» Water + Salt HC1 + NaOH-> H2O + NaCI Hydrochloric Sodium Water Sodium Acid Hydroxid Chlorid We have here the reason for the chemical antidote for poisoning by acids or bases. The most common base used to counteract an acid poisoning is calcium hydroxid or lime water. Vinegar or lemon juice may be used for alkali poisoning. 5. Action with Carbonates. An acid will react with any carbonate to give carbon dioxid, water and a salt, and this reaction explains a number of very common processes. Acid -j- Carbonate -»Carbon Dioxid + Water + Salt 2HC1 + CaCO3 -*CO2 + H2O + CaCl2 Effervescent powders always have an acid, and a car- bonate, which react when they are put into solution. The blue paper of a Seidlitz Powder contains potassium and sodium tartrate and sodium bicarbonate. In the white paper is tartaric acid. When these are put in water and mixed the liberation of the carbon dioxid causes efferves- cence. Effervescing powders must be kept in a dry place, protected from the moisture of the air. Baking powder contains an acid substance and a carbonate which when moistened generate the carbon dioxid which causes the bread to rise. This chemical reaction is also the basis for one type of fire extinguisher; in one chamber is sodium bi- carbonate and in the other sulfuric acid. When they come in contact as the container is turned upside down, this same chemical action takes place. The carbon dioxid which is generated being heavier than air acts as a curtain 64 APPLIED CHEMISTRY FOR NURSES between the air and the fire and shuts off the supply of oxygen. Acids should never come in contact with marble since marble is largely calcium carbonate. 6. Acid and a salt. Acid and a salt will undergo a double decomposition to give another acid and another salt. HC1 + KI HI + KC1 Acids which dissociate into ions to a large extent are known as strong acids; for example, hydrochloric nitric, sulfuric. Weak acids are those which do not dissociate into ions to any marked degree, such as boric, acetic and tartaric acids. The terms strong and weak do not refer to concentration. The terms used here are Concentrated and Dilute. In mixing any acid with water, always add the acid to the water, stirring con- stantly, using cold water. Strong acids will destroy living cells and for this reason they are germicidal. Their use as disinfectants is limited owing to their action on metal and fabrics. Normally the stomach contains 2-4% of hydrochloric acid and this is essential for the proper diges- tion of protein food. It also acts as an antiseptic in the stomach. Gastric analysis is frequently done to determine the amount of hydrochloric acid present. An over-secre- tion of hydrochloric acid in the stomach is known as hyperacidity and an under-secretion is hypoacidity. It sometimes is necessary to give dilute hydrochloric acid to supply a deficiency. The strong acids are rarely used internally. All acids which are given internally should be well diluted and should be given through a glass tube. Normal urine is acid in reaction since many of the prod- ucts resulting from body metabolism have an acid reac- ELECTROLYSIS. IONIZATION. ACIDS 65 tion. There are certain drugs which will only act in an acid medium. For example, hexamethylenamine frees formaldehyd only in an acid medium. If the urine is not acid another drug must be given which will render it so. Organic Acids.-All acids which contain carbon are known as organic acids and these will be discussed in connection with organic chemistry. Outline for Study I. Electricity a. Conduction b. Kinds of electricity c. Electrolytes II. Ionization a. Defined b. Effect c. Substances which ionize d. Effect on boiling point and freezing point of electro- lytes III. Acids a. Formulas of common acids b. Acid defined c. Common properties (1) Action with indicators (2) Action with metals (a) Practical application (3) Action with bases (a) Practical application (4) Action with carbonates (a) Effervescing powders (&) Effect on marble 66 APPLIED CHEMISTRY FOR NURSES (c) Baking powders (d) Fire extinguishers (5) Action with a salt IV. Strong and weak Acids a. Depends on ionization 1). Meaning of concentration c. Effect on cells V. Acids in the Body a. Hyperacidity 1). Hypoacidity c. Administration of acids CHAPTER VIII Bases. Acid and Basic Oxids Bases in solution will carry an electric current and are therefore electrolytes. A base is composed of a metal and oxygen and hydrogen. The oxygen and hydrogen are firmly bound together and the unit is known as the hydroxyl radical. These substances are also known as hydroxids. As with acids, let us enumerate the common characteristics. Take, for instance, sodium hydroxid or lye and put a little in solution. It would show the follow- ing characteristics: 1. Slippery feeling. 2. Reaction with an acid to give water and a salt. Sulfuric acid -|- Sodium Hydroxid -> Water -f- Sodium Sulfate H2SO4 4- 2NaOH -> 2H0H + Na2SO4 The hydrogen ion of the acid neutralizes the hydroxyl ion of the base and water is formed. The metal unites with the acid radical and forms a salt. 3. Action with indicators. a. Turns red litmus blue. b. Turns colorless phenolphthalein red. c. Red methyl orange becomes yellow. 67 68 APPLIED CHEMISTRY FOR NURSES Formulas. NaOH Sodium Hydroxid. Caustic Soda Yr KOH Potassium Hydroxid. Caustic Potash J ye" Ca(OH)2 Calcium Hydroxid. Slaked Lime. Dissolved in. water is lime water. Fe(OH)3 Iron Hydroxid. NH4OH Ammonium Hydroxid. Ammonia Water. Mg4(OH)2 Magnesium Hydroxid. Suspension in water is milk of magnesia. An examination of these formulas shows that the metal may differ but the hydroxyl radical is always present. It is the hydroxyl ions, then, to which the common char- acteristics of bases in solution are due. There is one ex- ception to the rule that a base is composed of a metal and the hydroxyl radical and that is in the case of ammonium hydroxid. The ammonium radical is NH4 but it acts chemically like a metal. Ammonium only exists in com- bination with the hydroxid or with a non-metal, for ex- ample, ammonium chlorid. The hydroxids of sodium, potassium, ammonium, and calcium only are soluble. When a base in solution is separated by an electric current the metal goes to the negative pole and the hydroxyl to the positive pole. A strong base, such as sodium hydroxid or potassium hydroxid is called an alkali. Any substance which in solution gives a basic reaction is said to have an alkaline reaction, and is commonly termed an alkali. In organic chemistry we shall find there are substances which have an hydroxyl radical, but are not bases. Strong alkalies, such as sodium hydroxid and potas- sium hydroxid, have decomposing properties and will decompose organic matter. For this reason they have germicidal value. They will decompose glass as will be noted from the laboratory bottles containing these solu- BASES. ACID AND BASIC OXIDS 69 tions. They are used in making soap. As they are ex- tremely caustic to the skin, any soap or soap powder con- taining free alkali should not be used on the skin. Most of the yellow laundry soaps contain free alkali. They should not be used for washing silk, woolen or linen. They may be used for washing white cotton goods except baby clothes. This is especially true of diapers. If the soap is not thoroughly removed when the diapers become wet, the alkali may cause very severe excoriation of the baby's skin. Soap powders consist largely of fine chips of soap and sodium carbonate, which we shall see later has an alkaline reaction in solution. We have already noted that aluminum will free hydro- gen from sodium hydroxid, so that strong soap powders should not be used in cleaning aluminum ware. Am- monium hydroxid in solution is used in the household in washing and cleaning to soften the water. It will dis- solve the tarnish on copper and brass, but the article must then be thoroughly washed in soap and water. The alkalies commonly used to counteract acidity in the stomach are lime water or calcium hydroxid, and sodium bicarbonate. Sodium bicarbonate may be used to neutralize hyperacidity in the stomach since the hydrochloric acid to which the condition is due, will react with it. H Cl + Nall CO3 -> H2O + CO2 + Na Cl Hydrochloric acid Sodium bicarbonate Water and Sodium carbon dioxid chlorid That carbon dioxid gas is liberated is evidenced by the eructation of gas which follows its administration. Sodium citrate is a.salt, but it has an alkaline reaction in the body. 70 APPLIED CHEMISTRY FOR NURSES All three of these alkalies are used in infant feeding to prevent the formation of large, hard curds in the stomach. Alkali Burns. For burns by alkali, whether externally or internally, since the taking of the alkali internally causes a similar action on the mucous membrane as it does on the skin, the first aid treatment is to use a dilute acid, such as vinegar, which is acetic acid, or lemon juice, which contains citric acid. Solutions of lye should never be left where there are children. Very severe injury is caused by drinking these solutions. The lye burns the lining of the esophagus and eventually there is the formation of scar tissue and a stricture may result. Acid and Basic Oxids.-There are certain oxids which will undergo a reaction with water to form acids and bases. A basic oxid is a compound of a metal and oxygen which when it enters into combination with water reacts to give a base. An acid oxid is a compound of a non-metal and oxygen which when it enters into combination with water reacts to give an acid. Take, for instance, calcium oxid or quicklime, which is used in the making of mortar and plaster; when this reacts with water calcium hydroxid or lime water is formed, CaO -j- H2O -> Ca(OH)2. Magnesium oxid in water re- acts similarly and for this reason may be used to neutralize acidity in the stomach. Carbon is a non-metal which when burned in oxygen gives carbon dioxid, C + O2 -» CO2. This is an acid oxid. When this acid oxid is dissolved in water the resulting product is carbonic acid, CO2 4~ H2O -» H2CO3. When sulfur is burned in the air the product formed is sulfur dioxid, which in contact with water forms sulfurous BASES. ACID AND BASIC OXIDS 71 acid, S + 02 -> S02, S02 +II2O -» H2SO3, sulfurous acid. In disinfection with sulfur candles this is the prin- ciple involved. The sulfur is burned in the presence of moisture so that it is really sulfurous acid which does the disinfecting. The room must be sealed and the most satis- factory method is to place the sulfur in a small container which rests on two bricks in a large pan of water. Four pounds of sulfur should be used for every 1000 cubic feet of space. Kindling temperature may be provided by plac- ing a small alcohol pledget on the sulfur and igniting it with a match. Sulfurous acid is also used to bleach fruits and vegetables, as well as wool, silk and straw. Materials bleached by sulfurous acid have a tendency to turn yellow. Outline for Study I. Bases a. Common characteristics b. Action with acid c. Action with indicators d. Formulas II. Alkalies a. Defined b. Alkaline reaction III. Strong Alkalies a. Uses b. Yellow laundry soap c. Soap powders d. Burns IV. Basic Oxids a. Defined b. Lime water c. Magnesium hydroxid 72 APPLIED CHEMISTRY FOR NURSES V. Acid Oxids a. Defined b. Carbon dioxid c. Sulfur dioxid (1) Disinfection (2) Bleaching CHAPTER IX Inorganic Salts When an acid and a base react together, the resulting products are water and a salt. When hydrochloric acid is used with sodium hydroxid the resulting salt is sodium chlorid. When sulfuric acid is used with calcium hy- droxid the resulting salt is calcium sulfate. HCI + NaOH -> HOH + NaCI Hydrochloric Acid Sodium Hydroxid Water Sodium Chlorid H2SO4 . + Ca(OH)2 -» 2H2O + CaSO4 Sulfuric Acid Calcium Hydroxid Water Calcium Sulfate The acid in solution and the base in solution dissociate into ions, the acid giving hydrogen ions and the base hydroxyl ions. The hydrogen ions and hydroxyl ions combine to form water which does not dissociate appre- ciably into ions. The other product is a salt composed of a metal and an acid radical. The acid radical may con- sist of a non-metal only or a non-metal and oxygen. This reaction of an acid and a base to form water and a salt is known as the process of neutralization. The acid and the base lose their characteristic properties and the resulting products are neutral. Salts form a very important group of compounds from the standpoint of physiology and medi- cine. We shall have occasion later to refer to the mineral salts in the body. 73 74 APPLIED CHEMISTRY FOR NURSES Methods of Obtaining Salts.- 1. Acid + Base -» Water -f- Salt 2. Acid + Metal above hydrogen in activity -» Hydrogen + Salt Both of these reactions have been discussed in the reactions of acids and bases. 3. Acid + Basic oxid -» Water -|- Salt 2HC1 + MgO H2O + MgCl2 4. Acid + Salt -> Acid + Salt. An acid may react with a salt to give another acid and a salt. 5. Salt + Base -> Salt % Base A salt may react with a base to give another salt and a base. 6. Salt Salt -» Salt + Salt. This is an important reaction for a nurse to remember since it is at the basis of a number of important reactions; for example, Silver nitrate-|-Sodiuni chlorid ^Silver chlorid-|-Sodium nitrate AgNO3 + NaCI -> AgCl + NaNO3 As we have noted before, a drop of 2% silver nitrate is dropped into each eye of a new born child, as a prophy- lactic measure for the prevention of gonorrheal infection of the eyes. After a few minutes have elapsed the eyes are flushed with "normal" salt solution, which is a 0.9% solution of sodium chlorid. As only one drop of silver ni- trate is used the silver chlorid is soon precipitated and the continuous flushing with salt solution removes it. We have already noted that water contains mineral substances in solution, one of which is sodium chlorid, and for this INORGANIC SALTS 75 reason, distilled water is always used to make silver nitrate solutions. A solution of sodium cldorid is used as the first aid treatment for silver nitrate poisoning. Our first reference to a chemical change, that is of potassium iodid reacting with mercuric chlorid, is a similar reaction be- tween two salts. It is a safe precaution never to give two salts at the same time unless so ordered by the physi- cian. Nomenclature.-It will readily be seen from the fore- going that if the acid radical of sulfuric acid is in com- bination with a metal, the salt obtained is a sulfate; nitric acid, a nitrate; hydrochloric acid, a chlorid; carbonic acid, a carbonate; phosphoric acid, a phosphate; hydrobromic acid, a bromid; hydriodic acid, an iodid. The metals also combine with the acid radical of organic salts, giving acetates, tartrates, lactates, and citrates. The name of an acid or a base depends on the amount of oxygen present and a whole series of acids may be built up, and although the acids may not exist as such, their salts do. Acids and Salts Add Example Salt Example Prefix-Hydro Suffix-ic HC1 Hydrochloric Acid Suffix-id NaCl Sodium Chlorid Prefix-Hypo Suffix-ous HC10 Hypochlorous Acid Prefix-hypo Suffix-ite NaClO Sodium Hypochlorite Prefix- Suffix-ous HC102 Chlorous Acid Prefix- Suffix-ite NaC102 Sodium Chlorite Prefix- Suffix-ic HC1O3 Chloric Acid Prefix- Suffix-ate NaC103 Sodium Chlorate Prefix-Per Suffix-ic HC104 Perchloric Acid Prefix-per Suffix-ic NaC104 Sodium Perchloric 76 APPLIED CHEMISTRY FOR NURSES Acid and Basic Salts.-All salts are not neutral in reac- tion. When an acid with more than one replaceable hy- drogen reacts with a base with a less number of replaceable hydroxyls, an acid salt results. For example, phosphoric acid II3PO4 has three replaceable hydrogens. If sodium hydroxid were used in this reaction there would be only one hydroxyl. The resulting salt would be an acid salt, sodium acid phosphate. This is a salt which is frequently used in medicine to make the urine acid. H3PO4 + NaOH -> NaH2PO4 + H2O However, this would depend on the proportion of sub- stances used. If three molecules of the sodium hydroxid were used the tribasic salt, Na3PO4, would result, that is, the salt which is the result of complete neutralization. Likewise we may have basic salts. If a base with more than one replaceable hydroxyl is used with an acid with a less number of replaceable hydrogens, the resulting salt will be a basic salt. Here again it will depend on the pro- portion of substances used, so that the nature of the prod- ucts obtained as the result of a chemical reaction often depends on the proportion of the substances used. A com- pound which has the characteristics of an oxid and a salt is an oxysalt, or a "sub" salt, as Bismuth subnitrate, BiO.NO3. Double Salts.-The hydrogen of an acid may be re- placed by more than one metal; for example, potassium aluminum sulfate, or alum. Hydrolysis.-Certain salts when dissolved in water will undergo a double decomposition with the water, and this is known as hydrolysis. There are, however, other sub- INORGANIC SALTS 77 stances besides salts which hydrolyze, as will be noted in studying the chemistry of digestion. A salt which results from the neutralization of a weak acid by a strong base, such as carbonic acid and sodium hydroxid, when dis- solved in water will undergo a double decomposition with the water and give an alkaline reaction. For example Na2CO3 + H2O NaOH + H2CO3 Sodium carbonate Water Sodium hydroxid Carbonic acid Both a base and an acid have been formed but the acid is a very weak acid, and there are sufficient hydroxyl ions to give an alkaline reaction. The double decomposition is not complete since water is only slightly dissociated into ions. It is because sodium bicarbonate and sodium acetate undergo hydrolysis that they give an alkaline reaction in solution. In making solutions of sodium bicarbonate it must be remembered that the bicarbonates are converted into car- bonates at boiling point and the carbonate of sodium is washing soda. Solutions of sodium bicarbonate may be sterilized in air tight bottles. The carbon dioxid which is liberated will then re-combine when the temperature of the solution is lowered. The bottles in which it is sterilized, however, must be absolutely air tight. 2KaHCO3 Na2CO3 + H2CO3 There are other salts which in solution give an acid reac- tion, because a strong acid has been neutralized by a weak base; for example, copper sulfate, zinc sulfate, ferric chlorid. Hydrates.-Many salts enter into direct combination with water to form hydrates. The formula indicates that 78 APPLIED CHEMISTRY FOR NURSES water is present; hydrated copper sulfate, Cu SO45H2O- When a hydrate is heated the water is set free, leaving the anhydrous form of the substance, or the anhydrate. All hydrates are crystalline in form but all crystals are not hydrates. The water which is chemically united is called the water of crystallization or the water of hydra- tion. Copper sulfate hydrate is a bright blue crystal. If these crystals are heated the water of hydration is driven off and a gray powder results. Washing soda or sodium carbonate, magnesium sulfate, alum, borax, sodium phos- phate and many other well known compounds have two forms, the hydrate, or crystalline form, and the anhydrate, or powder. In the United States Pharmacopaea, a drug which has been heated to drive off the water of crystalliza- tion is called an exsiccated drug; as, exsiccated sodium phosphate. A drug from which water, not in chemical combination with the substance, has been removed, is a desiccated substance; for example, desiccated thyroid glands. A hydrate which is of special interest to nurses is cal- cium sulfate or gypsum. Crystals of gypsum when heated, give up water of crystallization and leave a smooth white powder, plastei' of Paris. This water of crystallization may be1 added again. Plaster of Paris splints and casts are used to immobilize a part in any desired position. The powder is spread on crinoline which has a coarse mesh. The powder is held in the mesh and when it is to be applied the bandage is submerged upright in a bucket of water which contains a small amount of salt. The bandage should be removed from the bucket when the bubbles come up through the center of the bandage. It is INORGANIC SALTS 79 then wrung gently to remove excess water and applied to the part quickly. The water immediately goes into chem- ical combination with the plaster of Paris and forms crystals. The crystals fuse together and harden and this fusion is accompanied by expansion, since it is only natural to suppose that the crystals will occupy more space than the powder. A cast or a bandage which may seem perfectly comfortable when applied may be very much tighter when it has hardened. It is therefore extremely important for the nurse to watch the circulation of the patient who has had a plaster of Paris bandage applied. Plaster of Paris may be easily removed from rubber gloves with sodium bicarbonate solution. Water in which plaster of Paris bandages have been submerged should be allowed to stand until the suspended matter has set- tled to the bottom of the container and hardened. The water may then with safety be poured off into the drain. Efflorescence and Deliquescence.-Many of these hy- drates will gradually lose their water of crystallization at room temperature. They are given the name of efflorescent substances. Sodium sulfate, sodium car- bonate, sodium phosphate and magnesium sulfate are efflorescent. A hygroscopic substance is one which absorbs moisture from the air at ordinary temperature. If it ab- sorbs sufficient moisture to become liquid, it is a deli- quescent substance. We have a good many drugs which are hygroscopic or deliquescent. Calcium chlorid, cal- cium bromid, lithium bromid, sodium nitrate, potassium acetate, and glycerin will absorb moisture from the air in various degrees, and for this reason stock solutions of 80 APPLIED CHEMISTRY FOR NURSES many of these substances are used. All efflorescent and deliquescent substances must be kept in tightly stoppered bottles in a cool place. Hard Water.-Hard water is due to the presence of soluble salts, and the softening of the water depends on changing these soluble salts to insoluble salts. If the water is hard and soap is used, a curdy substance separates on the top, because the soap has reacted with the soluble salt in the water to form an insoluble salt, which is precipi- tated. Until the soluble salt has reacted chemically with the soap or the chemical, which is added, to form insoluble salts, soap cannot exert its normal effect and produce a lather. The use of soap to soften water is wasteful when a much cheaper material, such as sodium carbonate may be used. At wholesale washing soda is 1% cents a pound, soap powder 314 cents a pound, and soap chips 8 cents a pound. There are two types of hard water, temporary and permanent. Temporary hard water is usually due to calcium acid carbonate and may be softened by boiling, which drives off carbon dioxid from the acid salt and converts it into the normal salt, calcium carbonate, which is precipitated, and forms the familiar "scale" found in the tea kettle, in districts where there is a good deal of lime stone. Ca(HCO3)2 -* CO2 + H2O + CaCO3 Permanent hard water is due to calcium or magnesium salts, largely chlorids and sulfates. Boiling has no effect on it. These salts must be precipitated by a chemical agent such as sodium carbonate or washing soda. Many hospitals now have a water softening plant, which results INORGANIC SALTS 81 in a lessening of the amount of soap needed in its various activities, and also results in better laundering. Clothes which are washed in hard water need special care in rinsing to avoid the harsh feeling which is the result of the salts which have been precipitated, clinging to the fiber of the goods. This is especially true of woolen materials. Outline for Study I. Neutral Salts a. Neutralization b. Methods of obtaining salts c. Double decomposition of salts (1) Practical Applications d. Nomenclature II. Other Salts a. Acid salts b. Basic salts c. Double salts d. Oxysalts III. Hydrolysis a. Defined b. Nature of the act IV. Hydrates a. Defined b. Exsiccated versus desiccated substance c. Plaster of Paris casts d. Efflorescence and deliquescence (1) Definitions (2) Practical application V. Hard Water a. Presence of soluble salts 82 APPLIED CHEMISTRY FOR NURSES b. Kinds c. Means of Softening (1) Effect of boiling (2) Use of chemicals CHAPTER X Some Common Metals and Thier Compounds It is not possible for us in the limited course which is given in our schools of nursing to study all the metals and their compounds, and we will simply make some brief statements about the more common ones. All the metals are solids with one exception, mercury. They are good conductors of heat and have a silver lustre with two excep- tions, gold and copper. The metals are usually found in nature in combination with other elements. When com- bined with the hydroxid radical, they form bases and they replace the hydrogen of acids to form salts. There are several important practical factors to be considered with metals; first, their reaction to the oxygen, carbon dioxid and moisture in the air; second, their reaction with acids; third, their reaction with salts. Many of the metals tarnish readily in the air, forming oxids or carbonates. For this reason an alloy has some advantages over the pure metal for practical purposes. An alloy is a mixture of metals. It usually has a lower melting point, is more durable and is less likely to tarnish than any of the metals of which it is made. For example, brass is an alloy of copper and zinc. In the discussion on hydrogen a list of metals is given arranged in order of their activity in freeing hydrogen 83 84 APPLIED CHEMISTRY FOR NURSES from water and acids. Reference was made to the fact that the position in the list also indicated the metal's activity in combining with oxygen and since we have studied "salts" we are now in a position to see another value in this list. Any element in this list will displace any one below it from its salts and it in turn may be dis- placed from its salts by any one above it. For example, mercury will displace silver from a solution of silver nitrate and nickel will displace mercury from bichlorid of mercury. Metal Alkalies.-The chemists have found that the ele- ments seem to group themselves together into families. All the members of the family have similar chemical proper- ties ; for instance, sodium, potassium and lithium are known as the metal alkalies. They are very active ele- ments, tarnishing readily when exposed to the air and when in contact with water free hydrogen. In the labora- tory they are always kept under kerosene and must never be handled with the fingers. Because they are such soft metals they are not used except in compounds. Many im- portant salts used in medicine are compounds of these elements. Alkali Earth Metals.-Calcium, strontium, barium, magnesium, and radium are the alkali earth metals. In our own work, we are more familiar with these elements, in the form of their compounds. They, too, will decom- pose water, though not as readily as the metal alkalies. The calcium ions in the blood are important factors in the clotting of blood. Two important compounds of cal- cium are calcium oxid, or quicklime, and calcium hy- droxid, or slaked lime, which in solution is lime water. SOME COMMON METALS 85 Slaked lime is used in making mortar and plaster. When the water used for mixing evaporates, the mortar and plaster begin to harden owing to the action of the carbon dioxid in the air upon the slaked lime. A similar reac- tion takes place when bottles of lime water are left stand- ing in the air without stoppers. Ca(OH)2 + CO2 -> Ca CO3 + H2O This reaction is the basis for the test for carbon dioxid. Bleaching powder or chlorinated lime is well known to us for its disinfecting powers. Precipitated chalk used in tooth powder is also a form of calcium carbonate. Limestone, marble, pearls, corals and various sea shells are largely calcium carbonate. Calcium phosphate is the chief mineral salt in bones. We have already dis- cussed calcium sulfate or gypsum. Strontium salicylate and strontium bromid are the principal strontium com- pounds used in medicine. Barium sulfate is used in X-ray work. It is insoluble in water, dilute acids and alkalies, and will pass through the entire gastro-intestinal tract without change. A paste is made with this salt and when it is swallowed, it coats the lining of the stomach and intestines and thus gives the contour of these organs as well as showing the length of time it takes for the substance to pass from one portion of the alimentary canal to another. Magnesium sulfate is used as a cathartic and also for dressings to allay inflammation. Other compounds of magnesium, the oxid and milk of magnesia, are used as alkalies. Radium. A few facts about radium will be of interest 86 APPLIED CHEMISTRY FOR NURSES to nurses because of the growing importance of the use of its salts in the treatment of cancer. Radium has the peculiar property of emitting active rays upon which its therapeutic activity depends. A substance which emits these rays which penetrate objects opaque to ordinary light is known to be radio-active. Radium is in a process of constant disintegration with a production of a relatively large amount of heat. It is the greatest source of energy known. One gram of radium in its disintegration pro- duces about 100 calories of heat every hour. Radium dis- integrates so slowly that after approximately 1700 years one half of it still remains. The first product of disinte- gration is called radium emanation and emits rays which are valuable in treatment of cancer. It is removed from the radium into very small capillary glass tubes. The amount is measured in millicuries. The life of the emanation, however, is very short so that the so-called radium waters are not reliable. Its strength is decreased about one-sixth each day so that it is necessary to remove a fresh supply every few days. The value of radium as a therapeutic agent is due to the fact that it destroys can- cerous tissue more rapidly than normal tissue; however, it produces the most severe burns and must be handled very cautiously. It must not be carried in the hands and while thin lead containers offer protection it is only harmless in very thick lead containers. Iron and Nickel.-Iron and nickel are closely allied. We have already referred to both of these in connection with oxygen. Iron forms two series of compounds. In one series, the iron has a valence of two and its compounds are ferrous compounds. In the other series, iron has a SOME COMMON METALS 87 valence of three and its compounds are ferric compounds. Iron is a constituent of the hemoglobin of the blood and its administration in medicinal form is indicated in anemia. Foods rich in iron are also indicated. Iron preparations should always be given through a glass tube so as not to corrode the enamel of the teeth. The rusting of iron in the air is not a direct combination with oxygen, since this does not occur in dry air, but there is prelim- inary action with water in the air. Iron salts may be present in water and they become apparent in the oxidized form as rust after the articles washed in the water have been laundered. Iron rust may be removed from white goods by stretching the article over a bowl of hot water and applying weak hydrochloric acid with a glass rod. The article should be dipped into the hot water between applications of the acid and then neutralized with a weak solution of ammonium hydroxid. The blue black writing ink is a solution of ferrous tannate. This solution is colorless and in order to make the writing visible a blue dye is added. On exposure to the air, the ferrous tannate is oxidized to ferric tannate, a black insoluble salt. Since ferrous tannate, as well as the dye, is soluble in water, fresh ink stains may be re- moved from fabric by washing it in water. To remove old stains it is necessary to reduce the ferric salt to ferrous tannate. A weak solution of oxalic acid or citric acid from lemon juice will remove the stain. Nickel may be kept bright by washing with dilute am- monium hydroxid and polishing with a soft cloth. Kero- sene will remove any grease from nickel. Nickel plated instruments should always be boiled in water to which 88 APPLIED CHEMISTRY FOR NURSES has been added a small amount of sodium bicarbonate or the normal carbonate. Copper, Mercury and Silver.-Copper, mercury and silver have similar chemical characteristics. Copper is a hard red metal and will not decompose water. In moist air it is acted upon by the oxygen and carbon dioxid and becomes coated with a green carbonate. This carbonate may be dissolved by ammonia water or oxalic acid but the copper must then be washed with hot water and soap. Dilute acids, as a rule, do not act upon it unless the air has access to it. Copper utensils used for cooking must be kept free from tarnish as any organic acid in the food will react with the tarnish to form poisonous salts. Like iron, it forms two series of compounds, cuprous compounds and cupric compounds. Cupric sulfate or copper sul- fate is used as a germicide and insecticide. Cupric oxid is a black insoluble substance while cuprous oxid is a brick red color and is the oxid which is produced by the action of reducing sugars on Fehling's solution. Mercury is the only metal which is a liquid. It boils at a high temperature and solidifies at a low temperature. The action of heat and cold in expanding and contracting it is readily observable and for this reason it is used in thermometers. Again we have a substance which forms two series of compounds, mercuric and mercurous. Mer- curic chlorid is bichlorid of mercury or corrosive subli- mate. It is extremely poisonous and is used in very diluted solutions as a germicide. It will corrode metals. It will coagulate protein, forming an insoluble albuminate, hence the use of white of egg as a first aid antidote in case of poisoning. This action also limits its use as a disin- SOME COMMON METALS 89 fectant for body excretions. Mercuric chlorid will react with other salts and a solution of calcium sulfid given intravenously is now being used as an antidote for poison- ing. In mercurial poisoning if colonic irrigations and gastric lavage are ordered, it is important that the fluid used for the washing be saved, as the physician may wish to have it tested for mercury. Mercurous chlorid is calo- mel, which is used as an intestinal antiseptic and cathartic. Mercury has long been known as a specific in syphilis. With any mercury compound, the nurse must be con- stantly on the watch for symptoms of mercurial poison- ing. In giving inunctions of mercurial ointments, rubber gloves should always be worn. Silver is a white metal with a high luster and is not acted upon by the oxygen of the air or water, but sulfur acts with it readily, forming silver sulfid, as will be noted when the sulfur from egg yoke comes in contact with a silver spoon. Silver objects become black in a room lighted by illuminating gas, due to the combination of the silver with the sulfur in the gas. Oxidized silver has a thin coating of silver sulfid. Silver may be cleaned by mechanically removing the tarnish, as by the use of a silver polish, or by using a substance which dissolves the silver sulfid. This latter may be accomplished by placing the silver in an aluminum pan containing two teaspoon- fuls of sodium bicarbonate to a quart of water. Other Metals.-Aluminum. Aluminum, also called aluminium, looks like tin. It does not change in dry air, but its luster is dimmed in moist air. It is very strong and very light. Hydrochloric acid will dissolve it but the acids in various vegetables have but very slight 90 APPLIED CHEMISTRY FOR NURSES action on it. Caustic alkali will attack it readily, liberat- ing hydrogen as we have already noted. Salt solution will also corrode it. Zinc.-Zinc has a bluish white color and a high luster. The air has no effect on it and therefore it is used exten- sively to cover iron, which is then called galvanized iron. There is a superficial tarnish in moist air. Zinc oxid is a pure white powder which is used in the form of an ointment as well as a dusting powder to allay irritation. Adhesive plaster is made with zinc oxid and a combina- tion of balsams and resins. Zinc oxid is insoluble in water, as are balsams and resins, and for this reason, water will not remove adhesive plaster. Some substance, such as benzine, naphtha or ether, in which the balsams and resins are soluble, must be used. The fact that zinc oxid is insoluble in water makes it a valuable ointment to use in protecting the buttocks of incontinent patients and for the excoriated buttocks of children since the zinc oxid, as well as the base of the ointment, benzoinated lard, is impervious to moisture. Lead and Tin.-All lead compounds are poisonous. Acids act on it forming lead salts. Soft water with the oxygen and carbon dioxid in the air react with lead to form compounds, which when dissolved in the water, ren- der it unsafe for drinking. Lead is very slowly eliminated from the body and cumulative lead poisoning occurs among workers in industries where lead is used. For- tunately this is not as common as formerly, due to legis- lation and the education of employers and employees as to its danger. "Lead water" is a diluted solution of lead subacetate and is used in skin conditions. Tin forms SOME COMMON METALS 91 two series of compounds, stannic and stannous. Tin is used largely as a protective covering for other metals ■which are readily acted upon by the air. Platinum and Gold.-Neither platinum nor gold are acted upon by the ai^ at ordinary temperature nor are they acted upon except at a very high temperature. For this reason, platinum is very valuable for laboratory equip- ment. Outline for Study I. Metals a. Common characteristics b. Alloys II. Metal Alkalies a. Action in air b. Action with water III. Alkali Earth Metals a. Calcium compounds b. Barium sulfate and its use c. Magnesium compounds d. Radium (1) Radio-activity (2) Radium emanations IV. Irons and Nickel a. Ferric and ferrous compounds b. Administration of iron preparations c. Rusting of iron d. Iron rust on clothing e. Care of nickel-plated instruments V. Copper, Mercury and Silver a. Action of moist air on copper b. Copper compounds 92 APPLIED CHEMISTRY FOR NURSES c. Mercury (1) Physical state (2) Effect of heat and cold (3) Mercuric chlorid and other compounds (4) Mercurial poisoning VI. Silver a. Tarnish and its removal VII. Other Metals a. Aluminum b. Zinc (1) Uses of zinc oxid c. Lead and tin (1) Lead compounds (2) Uses of tin d. Platinum and gold CHAPTER XI Some Important Non-metals and Their Compounds The non-metals have no common characteristics except that they are constituents of all acids and salts. Nitrogen.-Nitrogen forms 79% of the air. It is necessary to life since it dilutes the oxygen. Free nitro- gen is a colorless, odorless, tasteless gas and is slightly soluble in water. It is found in nature chiefly in the form of ammonia and the nitrates. Its combinations are largely with hydrogen and oxygen, and it is a constituent of many organic compounds. Animals must have nitro- gen in order to provide for the repairing and building up of the tissues, since nitrogen is an important element in protein material. • Man gets his nitrogen largely from animal sources and the cycle of nitrogen in nature is an extremely good illustration of the law of conservation of matter. Bacteria are important factors in making avail- able the nitrogen of the air and in organic substances for plant life. Ammonia.-Whenever a compound containing nitro- gen, carbon and hydrogen is heated in a closed vessel, so that air does not have access to it, the nitrogen combines with the hydrogen to form the gas ammonia, NH3. As nearly all animal substances contain these elements, many 93 94 APPLIED CHEMISTRY FOR NURSES of them give off ammonia when heated. Animal sub- stances may also give off ammonia when they undergo de- composition in the air, as will be readily observed when urine decomposes. Ammonia is a gas which in solution forms ammonium hydroxid NH4OII. When heated to a boiling temperature, ammonium hydroxid loses all of its gas. Ammonia may be reduced to liquid form by lower- ing its temperature and increasing the pressure. When the pressure is removed from the liquefied ammonia it passes back into the form of a gas and in doing so it ab- sorbs heat from the surroundings and therefore reduces the temperature. For this reason, it is used in the re- frigerating plants. Ammonium compounds are used in medicines as respiratory stimulants and the salts are* used as expectorants. Nitric Acid.-Nitric acid is a strong acid. If it is spilled on the clothing, it destroys it, and the stains may not be removed by using an alkali to neutralize it; in fact, stains are increased in color by the use of an alkali. Ni- tric acid decomposes giving off oxygen which makes it valuable as an oxidizing agent. Salts of Nitric Acid.-The most common salts of nitric acid are sodium, potassium and silver nitrates. In medicine it is the nitrites or the salts of nitrous acid, which are more frequently used. The most important ac- tion of the nitrites is the vasodilatation of the blood vessels, causing a lowering of the blood pressure. When the nitrates are taken into the body they are reduced to nitrites. Nitrites in solution are converted into nitrates when exposed to the air. Silver nitrate solution finds frequent use as a germicide. It reacts with soluble SOME IMPORTANT NON-METALS 95 chlorids, bromids and iodids. It leaves a black stain on organic matter which is exposed to the light. Stains may be removed by tincture of iodin, followed by ammonium hydroxid and hot water. Fused silver nitrate is used as a caustic. There are a number of oxids which are formed with nitrogen, the most interesting of these being nitrous oxid, which is a colorless gas with a slightly sweet taste. When it is inhaled it produces anesthesia. Bacteria and Nitrogen.-The fact that waste products of the body and dead organic matter are broken down to ammonia, shows the presence of bacteria. These bacteria are able to break down the organic nitrogeneous com- pounds into ammonia, and other bacteria are able to oxi- dize this ammonia to nitrous acid, IINO2. This nitrous acid may be neutralized by bases in the soil forming nitrites. Other bacteria oxidize the nitrites to nitrates in which form they are soluble and may be utilized by the plants. This process is known as nitrification. Nitrates in the absence of oxygen and in the presence of organic matter may be reduced by bacteria with the evolution of free nitrogen. This is denitrification. There are certain bacteria which are found on the roots of many legumes, such as the bean, pea and clover, which are able to take nitrogen from the air and transform it into nitrates, so that it is available for plant life. This process is called nitrogen fixation. Cyanogen.-When carbon unites with nitrogen, it forms a very poisonous gas, cyanogen. With one atom of hydro- gen in addition, it forms hydrogen cyanide which in solu- tion is known as hydrocyanic acid or prussic acid. This 96 APPLIED CHEMISTRY FOR NURSES is extremly poisonous and poisoning may result from inhaling the vapor. Halogens.-Fluorin, bromin, chlorin and iodin are known as halogens, a word which signifies "salt pro- ducing," since they will combine with metals, such as sodium and potassium to form salts. Chlorids, bromids, and iodids are a very important group of drugs. Fluorin is a yellow gas and is very active, so that it is not found in nature as an element. When it combines with hydro- gen it forms hydrogen fluorid which in solution is hydro- fluoric acid and is used for etching glass. The graduation on thermometers and glass graduates is made with hydro- fluoric acid. There are minute traces of fluorin in the bones and in the enamel of the teeth. Chlorin is a yellowish green gas, which finds valuable use as a dis- infectant and bleaching agent. For bleaching it is used largely in the form of bleaching powder. Chlorin will bleach only moist material. The chlorin reacts with the water and frees nascent (new born) oxygen which does the bleaching. The reactions which take place are Cl2 + H2O HC1 + HC1O 2HC1O -> 2HC1 + O2 The nascent oxygen probably then combines with the pig- ment of the material to form a colorless compound. The efficacy of chlorinated lime as a disinfectant is due to the chlorin which it liberates and chlorinated lime to be of value, should contain 30% of available chlorin, which reacts similarly with water to free oxygen as in the bleach- ing process. As chlorinated lime is reacted upon by the carbon dioxid and water in the air, freeing chlorin, it SOME IMPORTANT NON-METALS 97 should always be kept in air tight containers. Dakin's Solution contains sodium hypochlorite and acts as an anti- septic by oxidation in the same manner as free chlorin. Ordinary table salt is sodium chlorid. When chlorin combines with hydrogen it forms hydrogen chlorid, a gas which in solution is hydrochloric acid. Another important compound is potassium chlorate used in mouth washes and gargles. Bromin.-Bromin at ordinary temperature is a red brown liquid soluble in water, the solution being known as bromin water. The bromids are an important group of depressants and their action is due to the bromin ion lodin.-lodin is obtained from the ashes of sea weeds and from crude Chile saltpeter in the form of sodium and potassium iodates. lodin is found in the body in the thy- roid gland. The element iodin forms black shining crys- tals. It is very slightly soluble in water but freely solu- ble in alcohol, and is used in an alcoholic solution as an antiseptic. The solution is known as tincture of iodin, and contains 7% of iodin and 5% of potassium iodid. Old tincture of iodin should not be used since the alcohol may have evaporated and the strength of the solution be- come increased. On wet skin it forms blisters, lodin is administered internally in the form of iodids which have the specific property of absorbing abnormal cells, hence they are used for the absorption of gum- matous formations in the tertiary stage of syphilis. They are also used as expectorants due to their salt action. Goiter is more prevalent in regions where the water is low in iodin content. Small doses of iodids have been 98 APPLIED CHEMISTRY FOR NURSES administered in many localities as a prophylaxis against goiter and at least one city has made the practice of intro- ducing iodids into the city water supply with the same intent. In combination with hydrogen, iodin forms hydri- odic acid. This is used internally in the form of a syrup, lodin may be liberated from hydriodic acid by the oxygen of the air and the syrup acts as a protection as well as a means of diluting the acid. Any iodin compound which is colored more than a slight yellow should not be used as it indicates that the iodin has been set free. Iodoform is an organic compound of iodin. With starch paste free iodin gives a deep blue color. This is used as a test for iodin. lodin is set free from its compounds by oxidizing agents; for example, hydrogen peroxid. The halogens have the property of displacing one another; for ex- ample, chlorin will displace bromin from bromids and iodin from iodids. Bromin will displace iodin from iodids. Iodids should never be given with calomel (mer- curous chlor id). Phosphorus.-Phosphorus is very active chemically and never occurs naturally in the free state. There are two forms of phosphorus, white phosphorus and red phos- phorus. When white phosphorus is exposed to the air it combines with oxygen and gives out a phosphorescence in the dark. It is extremely poisonous. Where white phos- phorus is used in industries, it causes a necrosis of the bones of the jaw, and its use in the making of matches is illegal. On standing white phosphorus is converted into a dark red powder, red phosphorus. Calcium phosphate is the chief mineral constituent of bone. Phosphates are used as fertilizers. SOME IMPORTANT NON-METALS 99 •Arsenic.-Arsenic occurs as a free element as well as in compounds in nature. It is a steel gray metallic look- ing substance and is very poisonous. Arsenic is specific in syphilis and is the active principle in the arsphenamine compounds. Both arsenic and antimony resemble a metal in physical appearance and have many chemical prop- erties similar to metals. Fowler's solution contains arsenic trioxid and a nurse must constantly be on the watch for symptoms of arsenic poisoning. Sulfur.-Sulfur occurs in a number of allotropic forms. As we have already noted when sulfur burns in the air it forms sulfur dioxid, which in contact with moisture combines to form sulfurous acid which acts as a bleaching agent and a disinfecting agent. Sulfuric acid is a strong acid and is very largely used in the chemical laboratory as an oxidizing agent and as a dehydrating agent to remove water vapor from gases. In contact with compounds con- taining hydrogen and oxygen it will remove these elements in the form of water. For this reason, it will char most organic substances as wood, cotton and animal material, leaving carbon as a residue. The sulfates form a very important group of compounds. Silicon.-The compounds of silicon form about one- fourth of the crust of the earth. The element itself 'is a gray crystalline substance which is manufactured by heat- ing sand with coke. Sand is silicon dioxid. Glass is made by the action of calcium, sodium or potassium car- bonate with sand, the different carbonates being used to give different types of glass. Lead may also be used in order to obtain flint glass. Glass is completely oxidized and therefore does not burn. For use in the laboratory 100 APPLIED CHEMISTRY FOR NURSES hard glass is used and any glassware, such as flasks in which solutions are prepared for sterilization, should be of the best grade, otherwise the extreme heat may cause deposits of silicate to be found in the solution after sterilization. Boron.-Our chief interest in boron is in its compounds, boric acid and borax. Boric acid occurs in crystals and in a fine white powder. It is a very weak acid and finds frequent use as a mild antiseptic. It is found in many mouth washes and tooth powders. Borax is sodium tetra- borate. As this is a salt of a strong base and a weak acid it hydrolyzes and gives hydroxid ions. Its chief use in washing is to emulsify grease. Outline for Study I. Nitrogen a. Occurrence &. Importance to organisms c. Compounds (1) Ammonia (2) Nitric acid (3) Nitrates d. Bacteria and Nitrogen (1) Nitrification (2) Denitrification (3) Nitrogen fixation e. Cyanogen f. The halogens (1) Fluorin (2) Chlorin, uses and compounds (3) Bromids (4) lodin SOME IMPORTANT NON-METALS 101 (a) Uses of solution (&) Precautions (c) lodids (d) Hydriodic acid (e) Iodoform g. Phosphorus (1) Dangers (2) Compounds h. Arsenic (1) Compounds used in medicine i. Sulfur (1) Sulfur dioxid (2) Sulfuric acid (3) Sulfates j. Silicon k. Boron (1) Boric acid (2) Borax CHAPTER XII Carbon and Its Oxids Carbon.-Carbon is the one element which is common to all organic substances, whether the substance is a living animal or lifeless material, like wood. It is found in the crystalline and in the amorphous varieties. As crystalline carbon it occurs as diamonds and graphite. Diamonds are used for jewelry and to cut glass, while graphite finds frequent use in lead pencils and stove polishes. The amorphous carbon includes charcoal, coal and coke. Vast accumulations of vegetable matter which became mixed with water and earthy materials through the ages have been slowly changed to coal. Anthracite or hard coal we use chiefly to burn because of its chem- ical energy which is converted to heat when the coal is oxidized. Bituminous or soft coal is very largely used for the manufacture of artificial gases and to obtain coke. We shall have occasion to refer to this again. Charcoal.-Charcoal is a porous solid which absorbs gases and coloring matter from organic substances. It is used in the refining of sugar. Years ago charcoal was used for poultices on ulcers because of its absorptive power. Animal charcoal or bone black is obtained by heating dry bones. 102 CARBON AND ITS OXIDS 103 Carbon Dioxid.-The most common oxid of carbon is carbon dioxid, to which we have made frequent refer- ences heretofore, and much that we have to say here is in the nature of a review. It is a colorless, odorless, almost tasteless gas, slightly soluble in water and heavier than air. It is excreted by all animals in respiration. We may prove that carbon dioxid is given off in respiration by blowing through a glass tube into lime water. It will produce a white precipitate which is calcium carbonate. Another test for carbon dioxid is to dip a platinum loop into barium hydroxid and hold it over the substance evolving the gas and the film of barium hydroxid becomes barium carbonate, a white precipitate. This carbon dioxid which is excreted from the lungs is the result of oxidation of carbon in the body. A certain per cent of the carbon dioxid remains in the blood and has an important effect in stimulating the respiratory center. The amount of carbon dioxid in the blood is also an important factor to determine in certain diseases, since it indicates the degree of alkalinity in the blood. Expired air contains about of carbon dioxid. The burning of any organic substance such as wood, coal, gas and oil gives carbon dioxid. We might expect in certain places to find the proportion of carbon dioxid in the air much greater than in others. This is not so, however, since the total amount of air is so great in comparison to the carbon dioxid that it is dissi- pated rapidly in the air. Added to this is the fact that the plants take the carbon dioxid from the air and with the water from the soil and the sun as energy manufacture sugar. This process is called photosynthesis. The carbon 104 APPLIED CHEMISTRY FOR NURSES dioxid in the air is about 0.04%. A slight increase of carbon dioxid in the air has no material effect on health. Up to 5% may be breathed without appreciably affecting respiration. The carbon dioxid in the air is important to consider with certain metals such as copper. When plaster becomes hard it is due to the combining of the calcium oxid with carbon dioxid to form calcium car- bonate. When sugar is acted upon by the enzyme of yeast, carbon dioxid and alcohol are obtained. This same process takes place in the making of bread. The starch or flour is broken down by an enzyme into sugar and the enzyme of the yeast then ferments the sugar and carbon dioxid is evolved. This is what makes the bread rise. The carbon dioxid is driven off by the heat in baking and the meshes where it was held appear as the pores of the bread. We have already learned that carbon dioxid is evolved when- ever an acid comes in contact with a carbonate, and use is made of this in cooking when we want the dough to rise quickly. Cream of Tartar (potassium hydrogen tartrate KHC4H4O6) and sodium bicarbonate are fre- quently used as a baking powder. KHC4H4O# + NaHCO3 NaKC4H4O8 + H2CO3 -» HaO + CO, Sodium Potassium Tar- trate. (Rochelle Salt) Another method is the use of sour milk, which contains lactic acid, with sodium bicarbonate. Sufficient heat will drive off carbon dioxid from sodium bicarbonate but the resulting product, sodium carbonate or washing soda, would give an acrid taste to the bread or cake. We there- CARBON AND ITS OXIDS 105 fore use an acid substance which frees the carbon dioxid and leaves a product which is neither unpleasant nor harmful. Carbon dioxid is heavier than air and it will not allow substances to burn in it, hence the use of fire extinguishers which generate carbon dioxid by the interaction of an acid and a carbonate. Effervescing powders and car- bonated waters owe their effervescing properties to the liberation of carbon dioxid. Carbon dioxid is an acid anhydrid and therefore combines with water to form car- bonic acid, II2CO3. The acid is unstable and immediately decomposes into carbon dioxid and water. If a base is present also, salts of carbonic acid, the carbonates, are formed. The principal carbonates are marble, shells, lime- stone, which are all principally calcium carbonate, wash- ing soda or sodium carbonate, saleratus or sodium bicar- bonate and ammonium carbonate which is used as an expectorant and in aromatic spirits of ammonia and smelling salts. Carbon dioxid reacts with calcium hydroxid solution to form calcium carbonate. If an excess of carbon dioxid is added the precipitate dissolves because calcium acid car- bonate is formed. The latter is soluble. If the solution is heated the acid carbonate is decomposed and the cal- cium carbonate is again precipitated. We have already referred to part of this reaction in our discussion of tem- porary hard water. H2O + CO2 -» H2 CO3 H2CO3 + Ca(OH)2 -» CaCO3 + 2H2O CaCO3 4- H2CO3 -» Ca(HCO3)2 Ca(HCO3)2 -» CaCO3 + H2CO8 106 APPLIED CHEMISTRY FOR NURSES Carbon Monoxid.-Carbon monoxid is the oxid of car- bon which is produced when there is a maximum of car- bon and a minimum of oxygen. One sees it burning in the grate when there is a blue flame at the top of the fire. It is a by-product in certain industries, is used in illumi- nating gas and may be generated in automobiles, due to incomplete combustion. It is a colorless, odorless gas, and for this reason is very insidious. Fortunately it is usually combined with other gases which have an odor, which serve as a warning. When it is inhaled it unites with the hemoglobin of the red blood cells and forms car- bon monoxid hemoglobin, which is very stable. It is a saturated compound so that the red blood cells cannot carry any oxygen. The number of oxygen carriers in the body are reduced so that the cells do not get oxygen and as a result death ensues. The first aid treatment is to give oxygen. Carbon dioxid is also used in the treat- ment of monoxid poisoning. It stimulates the respira- tion and thus increases the amount of oxygen in the lungs as well as aiding in the elimination of the carbon monoxid. Outline for Study I. Carbon and its Compounds a. Forms of element b. Uses II. Carbon Dioxid Production a. In the body b. Yeast and sugar c. From carbonates (1) Important carbonates CARBON AND ITS OXIDS 107 III. Carbon Monoxid a. Production b. Action in the body c. Treatment for poisoning CHAPTER XIII Organic Chemistry Organic chemistry is a study of carbon and its com- pounds. The old idea of organic chemistry confined it to the study of compounds produced by the life activities of plants or animals. Later the gap was bridged by prep- aration in the laboratory of the same compounds which are produced in the animal body, and the limits of or- ganic chemistry had to be extended. We are particularly interested in organic chemistry since it includes the chem- istry of plant and animal life. It teaches the chemistry of the products which are used for food and medicine and it enables us to know their fate in the animal organism. As the field of organic chemistry now covers some hun- dred thousand compounds it is only possible in this short space to give the characteristics of a few of the important classes of organic compounds. Organic chemistry is built around the carbon atom with its valence of four. The structure of the organic molecule is very important. This concerns the arrangement of the atoms inside the mole- cule. In contrast to inorganic compounds it is possible to have organic compounds with identical chemical com- position yet with different properties due to the arrange- ment of the atoms. These compounds are called isomers. Since the structure of the molecule is so important it is 108 ORGANIC CHEMISTRY 109 very convenient to write the structural formula of the compound which shows to some extent the arrangement of the atoms. H H H I I I II -C -H H-C-C-OH I I I H H H Methane Ethyl Alcohol These two lormulas show how simple structural formulas are written. Each connecting bond represents one valence. You will note, as wre have learned before, that hydrogen has a valence of one, oxygen two, and car- bon four. Hydrocarbons.-A large class of organic compounds contain only carbon and hydrogen. They are, for this reason, named hydrocarbons. An important group of hydrocarbons is called the paraffin series. They are im- portant commercially because they are constituents of the ordinary motor, lubricating and burning oils. By dis- tilling crude petroleum there come off at different tem- peratures, first, gases, then the oils as benzine, gasoline, naphtha, kerosene, and remaining is a tar from which are obtained products like petroleum jelly and paraffin wax. Some of the paraffin series and their formulas are: Substance Formula Structural formula H I Methane CH4 H-C-H I H 110 APPLIED CHEMISTRY FOR NURSES Substance Formula Structural formula H H Ethane CaH„ H-C-C-H H H H H H I I I Propane C8H8 H-C-C-C-H H H H H H H H Illi Butane C4H10 H-C-C-C-C-H H H H H Note that each member differs from the one below it by CH2. The members given here are gases; the members above this in the series are liquids and finally we have solids. H H In certain hydrocarbons of which C = C H II Ethylene is an example we have less hydrogen in the molecule and the extra bond on the carbon is attached to the other carbon atom. Where the carbon atoms are joined by more than one bond the compound is said to be unsaturated. Ethylene is of interest because it may be used as a gen- eral anesthetic. It is very explosive. Acetylene has the formula H - C = C - H and is more unsaturated than ORGANIC CHEMISTRY 111 ethylene. This gas is used in the oxy-acetylene torches and for lighting. Alcohols. Characteristic Formula Group Structure Characteristic Example H - CH2OH C2H5OH or - C - OH - OH Ethyl Alcohol I H We will learn to distinguish the different classes of or- ganic compounds by certain characteristic groups or struc- tural formula arrangements, so that when we see this grouping we may know whether the compound is an alcohol, acid, aldehyd, etc. It will be noted, for instance, that the formula for ethyl H H II alcohol H - C - C - OH is simply the formula for H H ethane with one of the II atoms replaced by the OH group. This is known as substitution and is a very important type of chemical reaction in organic chemistry. Wood alcohol is methyl alcohol, CH3OH, and is ob- tained by the destructive distillation of wood. It is ex- tremely poisonous when taken into the body and will cause paralysis and blindness. It has assumed importance be- cause of its use as a denaturant to make grain or ethyl alcohol unfit for use as a beverage. 112 APPLIED CHEMISTRY FOR NURSES Grain or ethyl alcohol, C2H5OH, is made principally from the fermentation of grain and other vegetable prod- ucts. It is important as a solvent for many drugs and is used in all tinctures, spirits and elixirs. As alcohol evapo- rates readily these solutions must be kept well stoppered. We make use of this property of rapid evaporation by using alcohol for sponge baths. It also hardens the skin and acts as an antiseptic. An alcohol may have more than one OH group. H H - C - OH I H - C - OH H - C - OH H is glycerin, C3H5(OH)3, an alcohol obtained from fat as a by-product in the soap industry. As indicated by the OH group we may consider alcohols as organic bases because they may react with organic acids, forming esters. However we must consider the group very inactive in this respect because it does not give us any OH ions in solution. Aldehyds. Characteristic Formula Group Structure Characteristic Example - C = O - CHO HCHO Formaldehyd H ORGANIC CHEMISTRY 113 Our structural formula shows us that we do not have the OH present as in alcohols. Of the simple aldehyds formaldehyd is the only one of much importance to the hos- pital. It has a very pungent odor, is extremely irritating to mucous membranes, and is soluble in water to about 40 per cent. This solution is called formalin. Formal- dehyd is used as a disinfectant as it combines with the protein material of the microorganism. It is sometimes used illegally as a preservative for milk. A 4% solution is used to harden and preserve anatomical specimens. The fumes of formaldehyd in a room may be neutralized by ammonia fumes. With ammonia it forms urotropin. This is used as a urinary antiseptic in infections of the urinary tract, especially in pyelitis. Formaldehyd is only lib- erated from urotropin in an acid solution and for that reason acid sodium phosphate is generally given with it to ensure an acid urine. The aldehyd corresponding to ethyl alcohol is acetal- dehyd, CH3CHO. From this is made paraldehyd which is used as a hypnotic. As we shall see later the alcohol and the aldehyd groups are characteristic of the sugars. Alde- hyds will reduce, the metallic oxids. \ C\3 Ketones have the structure C = O. Acetone C = O ch3 is an example. The ketone structure is found also in the sugar, fructose or levulose. 114 APPLIED CHEMISTRY FOR NURSES Organic Acids. Characteristic Formula Group Structure Characteristic Example O - COOH CH3COOH // Acetic Acid - C O H Although we have an OH group in this structural ar- rangement it does not act as an alcohol. When dissolved in water the H atom will acquire a positive charge and the substance will be acid in reaction. Instead of writing acetic acid as CH3COOH it may be written HC2H3O2 which better shows it as an acid. The C2H3O2 is called the acetate radical in the same manner as NO3 is the nitrate radical. Most organic acids differ from most in- organic acids in that they are slightly ionized and are therefore weak acids. An important group of organic acids is the fatty acid series of which acetic acid is an example. This series will be illustrated further in a succeeding paragraph. The higher fatty acids, or those containing a larger number of carbon atoms, are important as we shall see later because they are constituents of ordinary fats. Acetic acid is the acid present in vinegar, and may be produced by the oxidation of alcohol by bacteria. Com- mercially it is produced by the destructive distillation of wood. When all the water is removed from it it will crys- ORGANIC CHEMISTRY 115 tallize and is called glacial acetic acid. Many of the salts, the acetates, are used in medicine. Other Organic Acids.-When milk sours lactic acid is produced by the bacteria acting upon the milk sugar. Its formula is CH3 CH(OH)COOH. You will note that it has a hydroxyl or alcohol group (OH) present, and is de- rived from the fatty acid, propionic, CH3CH2COOH, by substituting the OH group for one of the II atoms. COOH, Oxalic acid, I H.,Co04 is a constituent of some COOH plants and is present in normal urine in small quantities. You will note that it is composed of two COOH groups and therefore has two ionizable hydrogen atoms. The C2O4 group is the oxalate radical which has a valence of two. The formula of calcium oxalate would then be CaC2O4. Calcium oxalate crystals often occur in the urine. Oxalic acid is a reducing agent and for this reason is used in the removal of stains, such as potassium permanganate stains, ink spots, rust, from white goods. Tartaric acid is found in grapes. It also contains two COOH groups in its molecule and so is divalent. The tartrate radical is C4II4OG. The potassium acid salt KHC4H4O6 is cream of tartar and is used in medicine and in baking powders. Sodium potassium tartrate is Rochelle Salts. Citric acid is the acid of oranges, lemons, and grape- fruit. Its salts, called citrates, are used in medicine. Malic acid is found in unripe apples. All salts of these organic acids when taken into the body give an alkaline reaction because the body burns the acid radical to carbon 116 APPLIED CHEMISTRY FOR NURSES dioxid and water and leaves the metal free to act as a base. Comparison of Groups.-The relation of the preceding groups can be shown by the following table: Hydrocarbon Alcohol Aldehyd Fatty Acid CH4 CH3OH HCHO HCOOH Methane Methyl Alcohol Formaldehyd Formic Acid c2h8 c2h5oh ch2cho ch3cooh Ethane Ethyl Alcohol Acetaldehyd Acetic Acid c3h8 c3h7oh c2h5cho c2h5cooh Propane Propyl Alcohol Propylaldehyd Propionic Acid c4h10 c4h„oh c3h7cho c3h7cooh Butane Butyl Alcohol Butylaldehyd Butyric Acid C15H31COOH Palmitic Acid C17H35COOH Stearic Acid You will note as you proceed towards the higher carbon members that each one increases by CH2. Also as you proceed towards the right from a hydrocarbon to an acid each member is an oxidation product of the preceding one. Take for example ethane. Add one atom of oxygen and you have ethyl alcohol. From ethyl alcohol remove two atoms of hydrogen and acetaldehyd is formed. This is an oxidation because it requires one atom of oxygen to com- bine with the two hydrogens. Add one atom of oxygen to acetaldehyd and acetic acid is formed. The corresponding change from the fatty acid back to the hydrocarbon is one of reduction. The fatty acid series is so called because of the presence of the acids stearic, palmitic, butyric, which occur in nor- ORGANIC CHEMISTRY 117 mal fat. The formula for oleic acid, a constituent of nor- mal fat, is C17II33COOII. You will note that its formula is similar to that of stearic acid with the exception that it has two less hydrogen atoms. This is because it con- tains an unsaturated carbon group. When a large per- centage of it is present in a fat it is generally liquid at room temperature. Oils used in paints also contain un- saturated fatty acids and it is due to their oxidation by the oxygen of the air that they become hard and dry. Other Organic Groups. Esters: When an organic acid reacts with an alcohol an ester is formed. This corresponds to a salt in inorganic chemistry. Water is always one product of the reaction. C2H5OH + CH3COOH -> CH3COOC2H5 + h2o Ethyl Alcohol -j- Acetic Acid -» Ethyl Acetate Water Esters generally have a fragrant odor and are used to make artificial perfumes and fruit essences. An alcohol may also react with an inorganic acid. When amyl alcohol (CsHnOH) reacts with nitrous acid amyl nitrite is formed. Amyl nitrite is used in medicine to lower the blood pressure and to relax the spasm of invol- untary muscles as in asthma. It is usually given by inhalation. Nitro-glycerine is an ester of glycerine and nitric acid. An inorganic base and an organic acid will react to form a salt and water: thus we get our .salts, sodium citrate, potassium acetate, calcium lactate. Ethers: The ethers correspond to the oxids of inor- C2H5 ganic chemistry. Ethyl ether > O, is the only one C2H5 ' of importance. It is used as a general anesthetic. 118 APPLIED CHEMISTRY FOR NURSES Ethyl ether is an excellent solvent for most organic sub- stances and for this reason is used for the removal of grease stains and in the preparation of the skin for surgical pro- cedures. Ether is applied to the skin in order to dissolve the film of oil which is present on the normal skin. In many hospitals the procedure for the surgical preparation of the skin is first to use green soap and water, which re- moves dirt, alcohol next to remove any remaining mois- ture or soap and finally ether, to penetrate into the pores and dissolve the oil. It is extremely essential that when this preparation is in use that this sequence is followed. Ether is heavier than air and is extremely volatile. It should never be used where there is an open light except in extreme emergency and then the light must be held above the container of ether. Cans of ether which have been opened and left standing should not be used for anesthesia. Aromatic or Benzene Group.-In all the organic com- pounds that we have studied before this you have noted that the carbon atoms have been arranged in an open chain structure. They may also arrange themselves in a ring H C HC CH structure and benzene, 11 | , is the typical ex- HC CH \Z C H C6H6 ample of this structure. When an OH is substituted for ORGANIC CHEMISTRY 119 H O I C Z\ one of the H atoms phenol HC CH or carbolic acid is II I HC CH \// C H C6H5OH, formed. When the OH group is on the ring it reacts as an acid, ionizing into II ions, and does not have so many of the properties of the alcohols. Phenol is a germicide and is escharotic to the skin. For carbolic acid burns or poisoning the antidote is alcohol. When it is used as a cautery it is followed by alcohol to neutralize it. When CII3 is substituted for one of the II atoms in the benzene ring toluene is formed which is often used as a preserva- tive for urine. Substituting OH for II atoms in toluene gives us the cresols which are also very good antiseptics. When the acid group, COOH, is substituted for one of the C-COOH HC CH H atoms in the benzene ring benzoic acid HC CH C H is formed. Sodium benzoate has been much used as a pre- servative in foods as it has little if any physiological effect. 120 APPLIED CHEMISTRY FOR NURSES Substituting the COOH group for one of the H atoms C-COOH HO C-OH in phenol gives salicylic acid HC CH \// C I H Methyl salicylate is oil of wintergreen. Aspirin is acetyl salicylic acid. Coal Tar Products.-Many of the substances we have been discussing especially these derivatives of benzene, are called coal tar products because they are obtained by the destructive distillation of soft coal. It is heated out of contact with air and the distillate separated into its different constituents. Wood may be distilled in a similar manner. Halogen Derivatives.-The halogens, chlorin, bromin, and iodin may be substituted especially for hydrogen atoms and form compounds interesting to the nursing and medical professions. When three atoms of chlorin are substituted for three of the hydrogen atoms in methane, CH4, chloroform, CHC13, is formed. This is a colorless, heavy liquid with a sweet odor and is used as an anesthetic. It is not inflammable. If iodin is substituted instead of chlorin then we have iodoform, CHI3, which is used in antiseptic dressings. In case all four hydrogen atoms of methane are replaced by chlorin then carbon tetra- chlorid, CC14, is formed. This is valuable to remove ORGANIC CHEMISTRY 121 COAL Gas ' Illuminating Gas Ammonia Coal Tar Basis for Anilin Dyes Coal Tar Products Carbolic Acid Cresol Acetanilid Phenacetin Anti-pyrin Salicylic Acid Phenolphthalein Coke WOOD Gas Wood Tar Creosote Tar Gui a col Acetic Acid Charcoal Important Products Obtained from the Destructive Distillation of Coal and Wood 122 APPLIED CHEMISTRY FOR NURSES grease spots from clothing. It is safer to use than benzine or gasolene because it is non-inflammable. It is also a con- stituent of fire extinguishers like Pyrene. Here the heavy gas acts as a blanket and prevents the oxygen of the air from coming in contact with the burning material thus extinguishing the flame. When one of the hydrogen atoms in ethane is replaced by a chlorin atom ethyl chlorid, C2H5C1, is formed. This is used as a local anesthetic as it produces insensibility by freezing the part. When three chlorin atoms are substi- tuted for three hydrogen atoms in acetic acid, trichloracetic acid, CCI3COOH, is formed. This is a valuable protein precipitant. Halogens may also be substituted in the benzene ring. Compounds Containing Nitrogen.-Compounds con- taining nitrogen are important especially to the physio- logical chemist because of their association with nitrogen metabolism in the body. Amins. When a hydrogen atom is replaced by an NH2 group an amin is formed. CH3NH2 is methylamin. Amins are formed by putrefactive bacteria in the intes- tine. Metchnikoff believed these amins to be factors in the production of the symptoms of old age. They are heart stimulants and vasodilators. More important to the physiological chemist are the amino acids. They are formed in the digestion of protein in the alimentary tract and circulate in the blood stream. The following formulas show the relation of two of the simpler amino acids to the corresponding fatty acids. ORGANIC CHEMISTRY 123 CH3COOH CH2(NH2)COOH Acetic Acid Glycin CH3CH2COOH CH3CH(NH2)COOH Propionic Acid Alanin Amids. When the OH of the acid radical COOH is substituted by an NIL group an amid is formed. ch3cooh ch3conh2 Acetic Acid Acetamid Urea which is excreted in urine is an important amid. It is the diamid of carbonic acid. OH NH2 C = O 0=0 OH NH2 Carbonic Acid Urea Amins and amids react as bases and form salts with acids. Alkaloids are nitrogen containing chemical substances found in certain plants. They are basic and form salts with acids. The alkaloids are insoluble in water while the salts are generally soluble and they are administered as medicinals in this form. Morphin sulfate, strychnin sul- fate, caffein citrate, quinin hydrobromid are examples. Outline for Study I. Organic Chemistry a. Definition &. Isomers c. Structural formulas 124 APPLIED CHEMISTRY FOR NURSES II. Hydrocarbons a. Derivatives (1) Solids (2) Liquids (3) Gases III. Substitution Products of Paraffin Series a. Alcohols (1) Characteristic formula group (2) Methyl alcohol (3) Ethyl alcohol (4) Glycerin b. Aldehyds (1) Characteristic formula group (2) Formaldehyd (3) Paraldehyd c. Organic Acids (1) Characteristic formula group (2) Fatty acids (3) Fruit acids d. Relation of the groups IV. Esters a. Defined b. Reactions (1) Organic acid with alcohol (2) Alcohol with inorganic acid (3) Inorganic base with organic acid V. Ethers a. Uses of ethyl ether VI. Benzene Series a. Phenol b. Toluene c. Acids ORGANIC CHEMISTRY 125 VII. Coal Tar Products a. Destructive distillation of soft coal b. Important products (1) Gases (2) Coal tar (3) Coke c. Wood tar products VIII. Halogen Derivatives a. Chloroform b. Iodoform c. Carbon tetrachlorid d. Ethyl chlorid IX. Alkaloids a. Their nature b. Common alkaloids c. Action with acids X. Amins and Amids a. Amin group b. Amino acids c. Amids CHAPTER XIV The Chemistry of Foods There are certain definite characteristics exhibited by all living matter, whether it be a one-celled organism like a bacterium or a complex organism like man. All living organisms grow, repair and reproduce. They must take in food, water and oxygen and they must excrete waste products. They are capable of breaking down complex substances and then rebuilding them into material like themselves. This building up and breaking down process of the body is known as metabolism and it is due to chem- ical changes. From the moment of conception, through the intrauterine life and then from the entrance into the external world chemical changes are taking place; after death other chemical changes go on; these changes are all part of the great law of the conservation of matter. They may differ in the animal from that of the plant, but the essential thing in all the changes is the chemical action going on within the cell. Cells are made up of all the elements which are enumerated in our chapter on ele- ments, some having one combination and some another. But where does the body get these elements from which to build its cells ? Where does the energy come from which produces these changes ? In order to provide these elements for our cells, our foods must contain the elements which the body needs, and inherent also in these foods and in the oxygen which we breathe is chemical energy which be- 126 CHEMISTRY OF FOODS 127 comes apparent when the substances undergo chemical change. These elements we may find in the proteins, carbohydrates, fats, water, mineral salts and vitamins. We shall discuss each of these foodstuffs to see its chem- ical composition and then follow some of the chemical changes which take place within our own bodies. The Carbohydrates.-Carbohydrates are compounds of carbon, hydrogen and oxygen. They derive their name from the fact that they contain carbon and that the hydro- gen and oxygen are present generally in the same propor- tion as in water. When heated strongly the molecule will break, water will be liberated, and the carbon will color the remaining sugar brown or black. This is well known as caramelized sugar. One of the most common sugars is glucose or grape sugar. Good commercial com syrups are nearly pure glucose and are much used in making candy on a large scale. The formula for glucose is C6II12O6 and the structural formula is H H - C - OH H - C - OH H - C - OH OH - C - H H - C - OH c = o H 128 APPLIED CHEMISTRY FOR NURSES You will note the presence of the hydroxyl or alcohol groups (OH) and also the aldehyd group C = O. Most H of the characteristic sugar reactions are due to the latter group. Glucose is called a monosaccharid or hexose be- cause it has six carbon atoms. It is found in all plants, fruits, and in the percentage of about 0.1% in normal blood of animals. There are two other hexoses, levulose or fructose and galactose, which are important as being con- stituents of some higher carbohydrates. They have the same formula (C6II12O6) as glucose but certain of their properties are different because of the arrangement of the atoms in the molecule, in other words, they are isomers. Levulose is found in plants and fruits and galactose is produced in the body by hydrolysis of milk sugar. Another group of sugars is called the disaccharids be- cause they are formed of two molecules of monosaccha- rids with the loss of one molecule of water. Their formula is C12H22On. They may be broken down into their con- stituent monosaccharids. Sucrose (cane sugar) = glucose + levulose Lactose (milk sugar) = glucose + galactose Maltose (malt sugar) = glucose + glucose. Sucrose, prepared from the sugar cane and the sugar beet, is ordinary table sugar. Lactose is the sugar present in the milk of all mammals. Maltose is a very common sugar in both animal and plant life as it is formed in the hydrolysis of starches especially by enzyme action. Another group of sugars is called the polysaccharids CHEMISTRY OF FOODS 129 (C6H10O5)n as they are composed of an unknown number of molecules of monosaccharids with the loss of water. They include starches, gums, celluloses, glycogen, mucilages and the like. They are either in- soluble in water or form colloidal solutions. Raw starch forms a suspension in the water but when starch is boiled it forms a colloid. They serve largely as protection, struc- ture, or food storage for plant life. Glycogen is the animal starch and is present in the liver and muscles of animals. Starches are the only polysaccharids available as food for man, but some animals can use the celluloses. Starches exist in definite crystalline form in different plants and may be recognized with the microscope. When boiled with dilute acids they will break down into glucose and it is from cornstarch that most of the commercial glucose in this country is made. There are other less important hexoses, also five carbon sugars known as pentoses, and trisaccharids which contain three monosaccharids. As most of the simple sugars contain the aldehyd group they act as reducing agents and are themselves oxidized to acids. Fehling's test for sugar depends on the reduc- tion of a solution of cupric hydroxid to an insoluble, red cuprous oxid. Sucrose does not have a free aldehyd group and is the only one of the monosaccharids and disaccharids that does not reduce Fehling's solution. Another impor- tant property of sugars is their fermentation by yeast. Yeast contains an enzyme which will split a simple sugar into carbon dioxid and alcohol. An enzyme is an organic substance of unknown composition which will hasteji a reaction but not initiate it. It is an organic catalyst. It 130 APPLIED CHEMISTRY FOR NURSES is always a product of a living cell. Lactose is the only simple sugar which will not ferment with yeast and this property is used to distinguish it from other sugars. Plants obtain their carbohydrates by utilizing the carbon dioxid in the air. Green plants, that is, those which con- tain chlorophyll, are able to take the carbon dioxid from the air through the stomata in their leaves. This carbon dioxid unites with the water which is received by the plant through its roots and the sunlight furnishes the necessary energy to transform them into carbohydrate. The reac- tion is as follows: 6CO2 + 6H2O -» C6H12O6 + 6O2 In this way the plant gets its own carbohydrate food and stores it for the use of animals. The animals excrete carbon dioxid and in turn the plants use it. This is known as the carbon cycle and is still another example of the law of the conservation of matter. The Proteins.-The proteins are constituents of all ani- mal and plant cells and as a food are vital to the nutrition of all animal life. Proteins contain the elements carbon, hydrogen, oxygen, nitrogen, sulfur and sometimes phos- phorus. It is to the element nitrogen that they owe their chief importance. The structure of the protein molecule is unknown. The molecules are large and when they will dissolve in water, form a colloidal solution. The value of the proteins as nutrients depends upon their chemical con- stitution as shown by their cleavage or hydrolysis products. Their value as structural constituents of living material depends on certain physical characteristics such as solubil- ity, coagulability and lack of diffusibility. For conven- CHEMISTRY OE FOODS 131 ience proteins are classified into certain groups depending upon physical properties and composition. Only the more important groups will be mentioned. Simple Proteins.-Albumins are soluble in pure water and are coagulable by heat. Coagulation by heat is a phe- nomenon especially characteristic of many proteins when in contact with water. At a definite temperature their character is so changed that they separate from solution and will not redissolve. Albumins are widely distributed in animal and plant material. It is well to note that albumen is a name applied to protein material in general, especially the white of an egg, while albumin is applied only to a definite class of proteins. Globulins are insoluble in pure water but soluble in neu- tral salts of strong acids and bases, as for example, sodium chlorid. If you dilute the white of an egg with water the albumin will go in solution and you will note a flaky pre- cipitate throughout the solution. This is the globulin which has separated out. It was originally held in solution by the salt in the egg white, but precipitated when this salt was diluted with water. If you dilute blood serum with water it will become cloudy due to precipitated globulin, but if it is diluted with "normal" saline the salt will keep it in solution. Albuminoids are proteins which are characterized by a pronounced insolubility in all neutral reagents. Examples of this class are, elastin from ligaments, collagen from ten- dons, and keratin from the finger nails. Other simple pro- teins are the glutelins, prolamins, protamins, and histones. Conjugated Proteins.-Proteins are found conjugated with certain chemical groups and exist as such in 132 APPLIED CHEMISTRY FOR NURSES nature. The most important one is the hemoglobin of the blood, which is a combination of the pigment of the blood, hematin, with a protein molecule. Others are the proteins found in the mucin of mucous secretions, and phosphoproteins as the casein in milk and the protein of the egg yolk. Protein Derivatives.-In the breaking down of proteins into simpler molecules by the action of enzymes or other hydrolyzing agents cleavage products are formed which grow more simple in structure until the end products of the hydrolysis are reached. These derivatives are classi- fied as follows in the order of their complexity: PROTEIN Simpler protein (Metaprotein) Proteoses Peptones Peptids Amino acids. Some of these groups are not clearly defined and their reactions only indicate that as you proceed towards the amino acids the structure of the molecule grows less com- plex. The constitution of the eighteen or twenty amino acids so far obtained from protein hydrolysis is well known chemically. They all contain the -CH(NH2)COOH group and the remainder of the molecule is often quite complex. The body can build some of these amino acids and others must be supplied by the protein of the food. By determining the amino acids of a hydrolyzed protein much information can be gained as to the efficacy of the protein as a nutrient. CHEMISTRY OF FOODS 133 Protein Reactions.-It has been mentioned that pro- teins will coagulate with heat, that some are soluble in water and others not and those which are soluble in water form colloidal solutions and therefore will not diffuse through animal membranes. This non-diffusibility of pro- teins plays a very important part in the animal body. Were proteins readily diffusible we would have all our soluble body proteins excreted through the kidneys, but being non-diffusible they are retained in the blood stream while simpler substances are easily removed. When dis- ease injures the cell membrane in the kidney it becomes permeable and albumen appears in the urine. Proteins are precipitated by the salts of heavy metals such as silver, copper, lead and mercury salts. For this reason we give the white of egg as an antidote for poison- ing by these salts. As in the case of any antidote which reacts with the poison the product resulting from the chem- ical combination must be removed by lavage or gavage. Silver salts are used to cauterize because they act by pre- cipitating the protein and the same result is obtained as if it were coagulated by cauterizing with a hot iron. As a bacterial cell is composed of protein these heavy metallic salts act as disinfectants because they precipitate the pro- tein of the bacterium and render it lifeless. Practically all protein precipitants are good antiseptics and germicides. They are not effective for disinfecting stools, mucus, urine or vomitus as they precipitate any albumen which may be present and form a film of insoluble albuminate over the material, so that the mass is not disinfected. Proteins are precipitated by concentrated strong acids as sulfuric and nitric and with an excess of the acid they 134 APPLIED CHEMISTRY FOR NURSES redissolve acting as a base. Proteins react in the same manner with concentrated strong alkalies. Woolen goods being protein are readily attacked by both acids and alkalies. Proteins are precipitated by chemicals often known as alkaloidal reagents. Picric acid, tannic acid, phospho- tungstic are in this group. Tannic acid is used in tanning leather. The protein of the skin is precipitated by the tannic acid which renders it hard and prevents bacterial action. Its use as an astringent is a similar action. Two of the most efficient protein precipitants are trichloracetic acid and tungstic acid. When various salts as ammonium sulfate, sodium sul- fate, magnesium sulfate, and sodium chlorid are added in solid form to a protein solution certain proteins are precipitated unaltered in composition. The salt seems to render the water incapable of holding the protein in solu- tion. This process is known as salting out. Proteins have certain color reactions depending on chemical groups in the molecule. These are given in the manual at the end of the book. The Fats.-Fats are present in all animal cells and particularly in the fat deposits as in the omentum, the subcutaneous tissue, surrounding the heart and the kid- neys, and around the eyeballs. Fat is also quite widely distributed in the vegetable kingdom, especially in certain seeds and nuts. We have noted that when an alcohol reacts with an or- ganic acid an ester is formed. When the tri-hydroxyl alcohol, glycerol, reacts with three molecules of a higher fatty acid the product is an ester and is called a fat. CHEMISTRY OF FOODS 135 CH2OH + c17h35cooh c17h35cooch2 I I CHOH + C17HS5COOH -» C„H35COOCH + 3H2O I I cii3oh + c17hmcooh c17h35cooch2 Glycerol Stearic Acid -> glycerol tristearate (fat) or stearin -p water The glycerol ester of oleic acid is known as olein and that of palmitic acid is palmitin. Ordinary fats are a mixture of these esters. The more olein present the more liquid will be the fat. Some oils are about 95 per cent olein. Olive oil is largely olein. Some fats, for example, butter, contain esters of lower fatty acids. The reverse process of forming a fatty acid and glycerol from a fat is saponifi- cation. It is accomplished in the body by enzymes. It may also be brought about by the use of alkalies as sodium or potassium hydroxid in which case the sodium or potas- sium salt is formed instead of the fatty acid. The salt of a fatty acid is called a soap. If we use sodium hydroxid with olein, the resulting products would be sodium oleate (castile soap) and glycerin. C3H5(C18H33O2)2 + 3NaOH -» 3Na(ClgH33O2) + C3H5(OH)3 In the commercial manufacture of soap a mixture of fats is used and other substances such as rosin are used for fillers. Glycerol is an important by-product of the soap industry. The sodium and potassium soaps are soluble in water form- ing colloidal solutions. The former is hard soap and the latter soft soap. Calcium soap is insoluble in water and is the scum that is seen when soap is used in hard water, 136 APPLIED CHEMISTRY FOR NURSES due to the reaction of the calcium salts in the water with the soap. The reaction taking place, using sodium stearate, for example, would be 2Na (C18H85O2)+CaH2 (CO3)2 -> 2NaHCO34-Ca (C18H35O2)2 Calcium soap is soluble in kerosene so that the latter is an efficient agent to use in cleaning bath tubs, etc. Soaps are very good emulsifying agents. When two liquids are insoluble in each other they are said to be immiscible, for example, fat and water. By severe mechanical agita- tion, as by shaking, it is possible to disperse the fat in the water in very small droplets, and we have an emulsion. If the soap is dissolved in the water the fat will emulsify much more readily. It is perhaps due to this property that soaps are such good cleansing agents. A greasy film on the water in which dishes are being washed means that there is not enough soap to hold all the fat in emulsion. Cream and salad dressing are examples of good emulsions which remain as such for an extended time. Green soap is a solution of potassium or soft soap in alcohol. Good toilet soap should contain none of the alkali that has been used in its preparation. Soda lye (sodium hydroxid) is a good cleansing agent as it saponifies the fat with which it comes in contact. Fats are insoluble in water, slightly soluble in alcohol and soluble in the so-called fat solvents like benzene, ether, acetone and carbon tetrachlorid. Fats have few typical chemical reactions. They burn in the animal body to carbon dioxid and water and are very useful in supplying heat and energy. CHEMISTRY OF FOODS 137 Inorganic Salts.-Inorganic salts are a very essential part of the diet of the animal organism but nature has supplied them sb abundantly in our foods that it is neces- sary to add only one, sodium chlorid, to the average diet. We generally eat 10-20 gms. a day which is undoubtedly in excess of the requirements of the body and may even be detrimental. A large amount of inorganic salts is re- quired for the bony structures of our bodies. Inorganic salts have an important function in the regulation of the irritability of each cell, as well as being very essential in maintaining the osmotic pressure relationships of body fluids. Chlorids are important as a source of the chlorin for the hydrochloric acid of the stomach. Having sup- plied our sodium chlorid from a shaker, the other salt, of which there is likely to be a deficiency in our food, is the calcium salt. Cereals and tubers are relatively low in calcium and unless a diet contains sufficient leafy foods and milk it will be deficient in calcium. The correct amount of calcium and phosphorus is more important in the diet of young children and babes. A deficiency mani- fests itself in poor teeth and bone development, as well as definite pathological conditions such as rickets and tetany. The Vitamins.-In recent years it has been discovered that there are other essential factors in our diet besides the above well known food materials. They were, however, so abundant in a natural mixed diet that they remained hidden until civilization gave us canned foods, preserved foods, concentrated foods, synthetic foods and the like, in which the process of preparation destroyed these fac- tors. It was discovered in trying to feed animals with the best purified protein, sugar, fat and the proper inor- 138 APPLIED CHEMISTRY FOR NURSES ganic salts that they would not grow, but lost weight, be- came sickly, and died. From these experiments there has been shown to be at least three and probably more unknown substances which are best known as Vitamin A, Vitamin B, and Vitamin C. Vitamin A is abundant in cod liver oil, butter fat, tomatoes, and leafy vegetables. Many babes in Europe during the war developed a xerophthalmia due to a deficiency of this vitamin because they were compelled to drink skimmed milk. A lack of this vitamin is also con- cerned with the development of rickets and cod liver oil is very efficacious in supplying the deficiency. Well formed teeth are associated with an abundance of this vitamin. Vitamin B is abundant in yeast, milk, most cereals, most vegetables, especially tomatoes, cabbage, beans, potatoes and spinach, and in nuts. It is also called the antineuritic vitamin. In the past century beriberi was a very prevalent disease in the Orient until it was discovered to be due to the lack of this vitamin. The diet of these people was very largely white or polished rice, from which the outer covering, which contains the vitamin, had been removed. It is also associated with growth, and undernourished children are benefited by the inclusion of more of this vitamin in their diet. Vitamin C is the anti- scorbutic vitamin, the lack of which in the diet is associated with the disease of scurvy. It is present in fresh vege- tables and fruits and they were used for the prevention of scurvy on shipboard long before any idea of vitamin deficiency was surmised. It is the one vitamin which is appreciably destroyed by ordinary cooking and therefore the question of its supply becomes important where all cooked foods are used, or where boiled milk is used for CHEMISTRY OF FOODS 139 infant feeding. Canned tomato and orange juice are the most efficient sources of the antiscorbutic vitamin for infant feeding. The Complete Diet.-From this chapter we may sum- marize a few essentials of a complete and wholesome diet. The proteins must contain essential amino acids to be satisfactory. As proteins vary in the amino acid make-up, a variety of proteins will give a sum total having quality and quantity. It is well to remember that casein of milk is one of the most complete proteins and milk may well be taken in liberal amounts daily. The natural sugars and fats seem to be equally efficient in supplying heat and energy to the body. Although we cannot digest cellulose it is very important as a stimulus to peristalsis in the alimentary tract. A mixed diet will always contain a liberal amount of the inorganic salts with the exception of sodium chlorid and calcium salts. Primitive diets con- tain abundant accessory food factors or vitamins but as civilization advances and makes our diet more concen- trated and artificial it is well to remember where we may find a liberal supply of these factors. Outline for Study I. Living Matter a. Characteristics b. Cell as the unit c. Elements necessary d. Energy necessary e. How obtained II. Carbohydrates a. Groups 140 APPLIED CHEMISTRY FOR NURSES (1) Monosaccliarids (2) Disaccharids (3) Polysaccharids &. Action with Fehling's solution c. Carbohydrate of plants III. Protein a. Complexity of molecule &. Elements present c. Classes of protein (1) Simple (2) Conjugated (3) Derived d. Protein reactions (1) With heat (2) With salts of heavy metals (3) Other protein precipitants IV. Fats a. Composition b. Saponification c. Action of soap in hard water d. Emulsifying action V. Other food requirements a. Inorganic salts b. Vitamins (1) Importance (2) Deficiency diseases CHAPTER XV Digestion The food materials we have been describing are for the most part too complex to assimilate into the animal body. It is necessary to break these down into smaller molecules which are more diffusible and will readily pass through the intestinal wall. The simpler products are then ready to be used for the nutrition and energy of the body cells. The present chapter deals with the food as it enters the mouth and passes through the alimentary tract to meet with the various fluids with their potent digestive agents. Digestion is largely a story of enzymes with their specific, quiet and powerful action. Enzymes have certain opti- mum conditions under which they work best. Some act best in neutral medium, some best in alkaline, and some in acid. They also have an optimum temperature which for animal organisms is generally near that of body tem- perature, 37° C. (98.6° F.). Some vegetable enzymes have quite a different optimum temperature. Water enters into practically all enzyme reactions. Enzymes are gener- ally named from the substance (called the substrate) upon which they act and the word generally ends in ase. Those acting on proteins are called proteases, those on starch (amylum), amylases, those on fats (lipoids), lipases. In a similar manner, maltase acts on maltose, lactase on lac- 141 142 APPLIED CHEMISTRY FOR NURSES tose, sucrase (or invertase) on sucrose. Enzymes are de- stroyed by heating them much above their optimum tem- perature. Boiling destroys all enzymes. Enzymes are "poisoned" or destroyed by certain chemicals especially the protein precipitants. However, many antiseptics as toluol, chloroform, etc., do not appreciably hinder the action of a majority of them. When the three foodstuffs, protein, carbohydrates and fats are taken into the mouth they are thoroughly ground and mixed to a paste with the saliva. This contains only one important enzyme, the salivary amylase, ptyalin, whose important function it is to begin the digestion of the starches. It requires a neutral medium and has only time to act until the food becomes acid in the stomach. Its action is never complete and the process must be finished when the starch reaches the intestine. The end product of the reaction initiated by the ptyalin is mainly maltose. The proteins, fats, sugars and partly digested starches now pass into the stomach where they are gradually mixed with the gastric juice which is acid with hydrochloric acid. There are no carbohydrate splitting enzymes pres- ent. A fat splitting enzyme, lipase, is present but it has slight if any action in the acid medium. The important enzyme is the protease, pepsin, which in conjunction with the acid of the stomach begins the digestion of the protein material. Pepsin is excreted from the walls of the stom- ach in an inactive form, generally called pepsinogen, and becomes active in contact with the hydrochloric acid. It is probably important that it is secreted inactive, otherwise there might be the digestion of the gastric wall. Under DIGESTION 143 certain conditions this does occur and a gastric ulcer is the result. Considerable use is now made of the frac- tional analysis of the gastric contents to determine gastric function in its relation to certain pathological conditions. After a period of fasting a stomach tube of the Rehfuss type is introduced into the stomach and the gastric resid- uum removed. The patient is given a test meal generally of tea and toast. Samples of the gastric contents are removed generally every fifteen minutes and the acidity determined by titration. From this data such conditions as hypoacidity, hyperacidity, hypersecretion, etc., which have been shown to be related to gastric and duodenal ulcer and carcinoma, may be determined. The stomach also con- tains another protease called rennin which is especially active in infants. With the aid of the calcium in the milk it precipitates the casein, the milk protein. The precipi- tate is known as the curd. The enzyme rennin may be identical with pepsin. The digestion of the proteins is probably never completed in the stomach. They are gen- erally split to about the proteose stage. The stay of the food in the mouth and stomach has thus been more or less of a preparation for the action in the intestine. The food has been finely ground and mixed with the gastric juice. The splitting of the larger molecules has been started, and now the stomach ejects its contents into the intestine in small amounts for the completion of digestion. The reaction in the duodenum is alkaline due to the presence of alkaline carbonates and the acid chyme is gradually neutralized and made slightly alkaline which is the optimum reaction for the intestinal enzymes. As the chyme enters the intestine it is met by three important 144 APPLIED CHEMISTRY FOR NURSES fluids, the bile, the pancreatic juice and the intestinal juice. During the resting stage when food is not being digested in the intestine the flow of the pancreatic juice is small or absent. But as the acid chyme comes in contact with the intestinal mucosa a substance is liberated which enters the blood stream and travels to the pancreas. This stimu- lates the pancreas and juice is excreted. The substance is the hormone, secretin. The hormones are the chemical messengers in the body. The bile does not contain enzymes, but it does have the important function of help- ing to emulsify the fats which is very important for their digestion. We know this is true because when the amount of bile reaching the intestines is limited, due to disease of the liver or obstruction in the bile ducts, the stools are clay colored and they contain much more fat than normally. In these conditions the amount of fat in the diet is re- stricted. Bile also aids pancreatic digestion. The impor- tant enzymes of the pancreatic juice are: the protease in its inactive form called trypsinogen, pancreatic lipase, called steapsin, pancreatic amylase, called amylopsin. Sucrase, lactase, and maltase, are generally present but in small amounts and are not as important as similar enzymes in the duodenal juice. Pancreatic juice alone will digest protein little if any, but when it meets the intestinal juice the trypsinogen becomes active due to the presence of entero kinase in the secretion of the intestinal mucosa. It has now become trypsin and it takes the partly digested proteins coming from the stomach and carries the digestion further although perhaps not always completing it. The amylopsin completes the digestion of the starches to mal- tose while the steapsin is very active in digesting the fats DIGESTION 145 to glycerol and the fatty acids. The main function of the duodenal or intestinal juice itself seems to be to aid and complete the action of the pancreatic juice. It contains a protease, erepsin which acts best on the lower protein digestion products as peptones and proteoses, and the powerful sucrase, maltase and lactase which complete the digestion of the disaccharids. The digestion of the three foodstuffs is now complete. Remembering that each group of carbohydrates has the same empirical formula we may write the equation for the reaction which has taken place, but we must keep in mind that the equation only shows the beginning and the end result. There are intermediate stages in the process which are not repre- sented. It will be seen, however, that water is involved in each of the changes. Polysaccharids. (CJI10O5)n -J- nH2O -> nC6H12O„ Disaccharids. C12H22OU -|- H2O -> CgH12O, -f- CSH12O8 Sucrose Maltose Lactose Glucose Fructose " -{- Glucose " -{-Galactose The carbohydrates are in the form of the monosaccharids, glucose, galactose, and fructose. The proteins are broken down to their constituent amino acids; the fats are di- gested to glycerol and fatty acids, the latter having com- bined with the alkalies of the intestinal juice to form soluble soaps. These products are ready for absorption into the blood stream for distribution to the tissues. As far as we know water, inorganic salts, and the vi- tamins pass into the intestine and are absorbed into the body as such. Some inorganic salts, for example, magne- sium sulfate, are not absorbed from the intestine to any 146 APPLIED CHEMISTRY FOR NURSES extent. Other salts, for example, calcium lactate, enter into chemical reaction in the intestine and are excreted. Bacterial Action. After the enzymes have completed their work there is residue which they have been unable to attack. This passes on through the intestine and is valuable in giving bulk which acts as a stimulus to peristalsis. The contents of the small intestine are very liquid, and as such pass into the large intestine which absorbs much of the water and thus conserves it for body use. Patients with diarrhea are apt to become de- hydrated because of the great loss of water through the intestine. Bacteria thrive in the large intestine and putrefy much of the protein forming gases and other ob- noxious material as phenols, indole, skatol, and probably toxic amins. The products of this putrefaction when absorbed, act as poisons and must be detoxicated in the body. In ptomain poisoning putrefactive changes may have taken place and the poisons generated in the food before it enters the body. Most of the so called pto- main poisonings are in reality due to infections by bacteria of the paratyphoid and enteriditis group. The objectionable odor to fecal material is partly due to these putrefaction products. The stool of an infant fed on mother's milk has little or no odor. Indol is a substance for which the bacteriologist tests w7hen he suspects sewage pollution in water. The organisms are grown in peptone broth and after the incubation period, the broth is tested for indol. In the intestines there may also be fermenta- tion of sugar by the action of bacteria with the production of gases and acids, chiefly acetic, butyric and lactic acids. In the carbohydrate indigestion of infants there is a DIGESTION 147 considerable amount of flatus expelled and the stools are very acid in reaction, frequently causing excoriated but- tocks. Bacteria which cause fermentation of sugar do not thrive very well on a protein diet. In fermentative diarrhea of children, carbohydrates are eliminated and the protein intake is increased by the use of eweissmilch or other protein milk. Because of the ability of certain bacteria to ferment sugars they are used in culture media for bacteria, especially for the study of the colon typhoid group. The sugars generally used are dextrose, lactose, and mannitose, and the production of acid and gas is noted. Examination of the stools gives information in certain pathological conditions, but the microscopical examination is more valuable than the chemical. The presence of starch granules, excess fat, and meat fibers may indicate lack of pancreatic function. Feces are examined for neutral fat, or fat which has not been hydrolyzed, which would denote some interference with the digestion of fat, and also for fatty acids and soap. The last two in excess would show some interference with absorption. When an enema is given to obtain a stool for microscopic or chemical examination plain water should be used for the reason that if soap solution is used the stool will give a reaction for soap and lead to false conclusions. The pres- ence of "occult blood" in the feces gives evidence of a lesion in the alimentary tract as in carcinoma or gastric ulcer. 148 APPLIED CHEMISTRY FOR NURSES I. Digestion a. Necessity b. Enzymes (1) Function (2) Characteristics II. Hydrolysis of Carbohydrates a. Action in mouth and intestines b. End products c. Enzymes involved d. Fermentation of sugars III. Hydrolysis of Fat a. Action in stomach, and intestines b. Action of bile c. End products d. Saponification in intestines e. Soap stools IV. Hydrolysis of Protein a. Action in stomach and intestines b. Proteolytic enzymes c. Intermediate products d. End products e. Putrefaction of protein Outline for Study CHAPTER XVI Metabolism Metabolism is a broad term which covers all the changes that take place in living matter, both constructive and destructive. More specifically in the animal body it is the story of substances that enter the body, their reactions there and the recognition of how they leave. It implies energy as well as chemical change. The reactions are much more obscure than the digestive changes which we have been considering and most of our explanations are mere hypotheses. The field is so large that only a few substances can be considered. Absorption. The process of digestion left the food products in the intestine in a state capable of diffusion through the intestinal wall and capillaries into the blood stream. Water, amino acids, inorganic salts, and the vitamins are as far as we know absorbed as such. The monosaccharides are in some manner all converted into glucose during the process of absorption, or at least glu- cose is the only one recognized in the blood stream. Fatty acids and glycerol recombine again and enter the lymph circulation as neutral fats. Fats are absorbed through the lymphatics and not through the capillaries, and enter the blood stream through the thoracic duct. Amino acids are always present in the blood stream 149 150 APPLIED CHEMISTRY FOR NURSES and it is believed that they are directly connected with the nitrogen metabolism of the cell. Perhaps each cell is continually taking on and excreting amino acids. The end-product of this nitrogen metabolism is urea which also is always present in the blood stream. The following equations will illustrate the supposed mechanism of how the nitrogen of amino acids is changed to urea. Alanin is used as an example. CH3CHCOOH + H2O = CH3CHCOOH + nh3 I I nh2 oh Alanin -|- Water = Lactic Acid -j- Ammonia CO2 + H2O +2NH3 -> (NH4)2CO3 Carbon Dioxid+water-j- ES Ammonia=Ammonium Carbonate. o - nh4 nh2 C = O - 21LO -» C = O o - nh4 nh2 Ammonium Carbonate - Water - Urea. Note that water enters into all the reactions as it does in a majority of enzyme reactions. After the nitrogen has been split off the amino acid molecule in this process of deaminization the remainder may be used for the pro- duction of fats and carbohydrates or may be burned to carbon dioxid and water. When nucleoproteins break down in the body they yield a protein and nucleic acid. The nucleic acid further breaks down into uric acid. This is a constant constitu- METABOLISM 151 ent of the blood and is excreted as such in the urine. After eating calf's liver one would expect to find an increase of uric acid. Creatin and creatinin are important sub- stances present in blood and tissues but it is unknown how they are formed. Glucose is the sugar normally present in the blood stream although lactose has been reported in infants and nursing mothers. The quantity of sugar is increased dur- ing absorption after a meal and is often nearly double its normal value. This excess sugar is stored in the liver and muscles as glycogen, the animal starch, and as needed for energy it is reconverted to sugar so that the quantity in the blood remains fairly constant. Sugar is the first source that the body turns to for energy. When we work a muscle hard and must have energy the glycogen is pres- ent to supply sugar to be oxidized and produce it. The end-products in the oxidation of sugar are carbon dioxid and water. Fats are removed from the blood stream and stored in the tissues. They act as a reserve supply of energy. Be- sides the true fats there are other substances classed as lipoids which have many properties like fat. Lecithin is one of the substances present in blood and tissues. It contains fatty acids in its molecule, and may be related to fat metabolism. Cholesterol is a lipoid and is soluble in fat solvents. It is a large molecule and contains an alcohol group. It is an important constituent of the bile, and is always present in the blood stream. As we have indicated many times one of the impor- tant functions of the nutrients is to produce heat and en- ergy. The bomb calorimeter is an instrument for measur- 152 APPLIED CHEMISTRY FOR NURSES ing the quantity of heat furnished by a given amount of food. It consists of a steel tube in which the material to be burned and a given amount of oxygen are sealed. This is immersed in a vessel filled with water and so ar- ranged that the only heat which the water receives is from the inner tube. The material in the inner tube is ignited by means of an electric spark. As the quantity of water is measured it is easily figured how much heat the burning of the material produces. If we burn a definite amount of sugar in the calorimeter we will find that a definite amount of heat is formed. If we feed the same amount of sugar to an animal we find the same amount of heat formed in the animal as was formed in the calorimeter. The unit by which this heat is measured is called a large Calorie. It is the amount of heat re- quired to raise one kilogram of water one degree centi- grade. It has been found that each gram of protein we eat will supply about 4 Calories, one gram of fat, 9 Cal- ories and one gram carbohydrate, 4 Calories. One gram of protein does not supply as much heat to the body as when burned in the bomb calorimeter because the body does not completely oxidize the protein molecule but ex- cretes part of it as urea which still contains some energy. It has been found by long experimentation that persons of the same sex, age, height and weight require about the same amount of heat for their body needs when they are at absolute rest. In certain pathological conditions this amount of metabolism is changed and its determination has been made use of in clinical diagnosis. The basal metabolic rate is the amount of heat produced by an in- dividual at absolute rest without food. As all our oxida- METABOLISM 153 tion in the.body is dependent on the oxygen taken in through the lungs the basal metabolic rate may be in- directly determined by measuring the oxygen consump- tion over a given period of time. A person with a normal rate is considered as 100 and results are reported as plus or minus pei' cent variation from the normal, + 10 indi- cates 10 per cent above the normal rate of an individual of similar age, sex, weight, etc. The determination of basal metabolic rate is particularly valuable in disturb- ances of the function of the thyroid gland. It is extremely important that a patient to have a basal metabolism test should fast for twelve hours before the test, remain in bed during this time, and be taken to the metabolic station in the dorsal recumbent position and with no muscular effort on his part. It is also important that he should have no mental anxiety. Outline for Study I. Metabolism a. Defined b. Absorption c. Glucose (1) Oxidation (2) Storage (3) Source of energy d. Amino Acids (1) Function (2) Urea (3) Conversion into sources of energy e. Fats (1) Source of energy (2) Lipoids 154 APPLIED CHEMISTRY FOR NURSES (a) Cholesterol (&) Lecithin II. Measurement of Energy a. Calorimeter b. Basal metabolism (1) Defined (2) Test (3) Preparation of patient CHAPTER XVII Blood The blood is the circulating medium of the body. It distributes food and oxygen to all parts of the body where they may easily diffuse into the cells. It carries waste products to the proper organs for elimination. It dis- tributes heat and helps maintain body temperature at a constant level. It carries the products of internal secre- tion and the activators of many body processes. Blood is a sticky fluid, slightly heavier than water, and red in color. To the naked eye it appears homogeneous but under the microscope may be seen to have very small form elements or cells. These cells are the red corpuscles, white corpuscles and blood platelets. Normally there are about five million red blood cells per cubic millimeter, which carry the oxygen in the form of oxyhemoglobin to the cells. There are four or five types of white cells each having one or more nuclei. These are present in much smaller numbers than the red cells. Normally there are about eight thousand in a cubic millimeter of blood. The blood platelets are much less clearly defined form-elements. They have been associated with the clotting of blood. These form-elements are suspended in a slightly yellowish medium called the plasma. Plasma contains about 90 per cent water. About 85 per cent of 155 156 APPLIED CHEMISTRY FOR NURSES the solid matter of the plasma is protein and about 10 per cent inorganic salts. The main proteins of the plasma are fibrinogen, nucleoprotein, serum albumin and serum globulin. Fibrinogen is the protein which is changed to fibrin when the blood clots. Calcium is necessary for the clotting of blood as well as other unknown enzymes or activators. If blood is drawn from a vein and allowed to clot a clear liquid separates from the clot. This is known as serum and contains the same constituents as the plasma with the exception of fibrinogen which remains as fibrin in the clot. The principal inorganic salts of the plasma are those of sodium, potassium, calcium and magnesium, existing as the chlorid, carbonate, phosphate and sulfate. Sodium and chlorin are by far the most abundant elements. The blood cells contain little or no sodium, calcium and mag- nesium, but are rich in potassium existing as the chlorid and phosphate. There is much more phosphate in the cells but only about one half as much chlorin as in the plasma. Calcium phosphate is necessary for the building up of the bony tissues of the body. The "pipe stem" arteries which we feel on old people are due to deposits of calcium salts which have been precipitated in the walls of the arteries. An excess of potassium ions will cause the heart to beat slower, and for this reason potassium bromid, in contradistinction to the other bromids has a tendency to make the heart beat slower. Iron salts are necessary for new hemoglobin. These salts are the residt of chem- ical reactions in the body or are derived directly from the foods which are eaten. BLOOD 157 We have already noted that there is a small amount of oxygen in solution in the blood, and since the oxygen breathed in is diluted with nitrogen we find the lat- ter gas also present. As a result of oxidation of the sugars and fat carbon dioxid is excreted by the cells. Most of the carbon dioxid is carried as sodium bicar- bonate in the blood and in this combination is taken to the lungs for excretion. Besides the above mentioned constituents blood contains sugar, fat, cholesterol, lecithin, amino acids, acetone bodies, the source of which has been discussed under metabolism, and pigments. Since the tissues are con- stantly using these products or oxidizing them, or they are being excreted from the body the amount remains about constant. We must make mention also of enzymes, the secretions from the ductless glands, and the protective sub- stances, or antibodies. The lymph is the fluid bathing all the tissues. As the blood is confined to the capillaries the lymph is the carrier between these and the tissue cells. It resembles blood plasma and has been tenned ''blood without its red cor- puscles." Lymph is generally clear and transparent, but may be milky due to the presence of fat. Chemistry of the Blood in Disease.-One of the most interesting developments in medicine has been the chem- ical examination of the blood as a pre-requisite to clinical diagnosis and treatment especially in diabetes and dis- eases of the kidney. When the normal metabolism of a substance has been interfered with or when the excre- tion of a substance from the blood has been hastened or hindered the quantity of the substance present will gen- 158 APPLIED CHEMISTRY FOR NURSES erally have changed and may be an index of the patho- logical condition. While the nurse is not responsible for these tests, they are of interest and significance to her, since they are determining factors in the prognosis and treatment of her patients and she usually assists the doctor in obtaining the material for the test. A nurse who is aiding the physician in obtaining specimens for any chemical analysis, may ruin the result of the test by carelessness or ignorance. It is extremely important there- fore that when aiding with any test, or preparing pa- tients for scientific tests, that directions be carefully fol- lowed. From our own laboratory work, we have learned that accuracy in following directions is essential to sci- entific conclusions and interpretations. The nurse should not be a machine to record the results of laboratory tests. When she copies laboratory reports, the figures should have some significance to her. For example, Urea N 20 may mean a word and a figure or it may tell her a vital factor with regard to her patient's condition. Nephritis.-When kidney tissue has been damaged or destroyed by toxins or other poisonous substances it be- comes permeable to colloidal solutions and less permeable to many of the substances that it normally excretes. In most forms of nephritis albumen appears in the urine and substances as urea, uric acid, and creatinin are re- tained at a higher level in the blood stream. Chemical analysis of the blood shows the quantity of these sub- stances present and when they are above normal they are indicative of nephritis. The amount of nitrogen present from sources other than that of protein metabolism is not significant. The deter- BLOOD 159 urination of creatinin is of value to the physician in prog- nosis, since a patient with creatinin retention of 5 milligrams or over has very severe involvement and the prognosis is unfavorable. The normal values for these constituents expressed in milligrams per 100 cc. blood are: urea nitrogen, 12-15; uric acid, 2-3.5; creatinin, 1-2. Diabetes.-Certain cells of the pancreas secrete a sub- stance which is very necessary for the proper metabolism of the blood sugar. When these cells are damaged or destroyed blood sugar cannot be used by the body and it piles up in the blood stream. It is present normally at a concentration of about 100 milligrams per 100 cc. blood, but in diabetes it may increase to 200-G00 mgm. and in severe diabetes even as high as 1000 mgm. The kidney is not permeable to blood sugar at the normal con- centration but when it reaches about 200 or above sugar pours out into the urine. This important substance has recently been isolated from the pancreas and is called insulin. It is very valuable in the treatment of diabetes. The analysis of the blood for sugar gives valuable in- formation as to the severity of the disease, and it is of value in the control of insulin treatment. Besides the quantitative test for sugar in diabetes a test may also be performed to determine a patient's sugar tolerance. A specimen of blood is taken to de- termine the amount of sugar present after the patient has fasted for 12-14 hours. A solution of glucose is given by mouth, the amount being based on body weight, in the ratio of 1.75 grams of glucose to one kilogram of body weight. Specimens of blood are taken three quarters of an hour after the glucose is given and, one and two hours 160 APPLIED CHEMISTRY EOR NURSES later. Urine is collected before and after glucose is given. In a normal individual, the amount of sugar in the blood should return to normal in two hours and there should not be any excreted in the urine. Otherwise the person has a "decreased sugar tolerance." Persons may have an increased sugar tolerance in certain of the endo- crine disturbances. Acidosis.-The metabolism of the fats is intimately connected with the sugar metabolism. When the body is unable to use its sugar properly it is also unable to burn its fats completely to carbon dioxid and water and the so called "acetone bodies" are formed. These are acetone, diacetic acid, and hydroxybutyric acid. The latter two being acids require alkali in order to be excreted by the kidneys and to supply this deficiency the blood is robbed of its base (sodium) which is normally used to carry the carbon dioxid to the lungs. A more acid condition than normal is produced in the body and symptoms of acidosis are present. To diagnose acidosis either the car- bon dioxid carrying power of the blood (commonly known as CO2 capacity) or the true hydrogen ion con- centration of the blood may be determined. The latter is expressed as the pH of the blood. Normally the body maintains its reaction very constant. The pH is about 7.4. pH of 7.0 represents a severe acidosis while pH of 7.8 represents an alkaline condition sometimes known as an alkalosis. There are other forms of acidosis than that of diabetes particularly the acidosis of nephritis and in- fantile acidosis. A mild acidosis is frequently seen fol- lowing an operation. This is due to the anesthesia and in part to the starvation period which has preceded. This BLOOD 161 is especially true with children. Children tolerate hunger poorly and hence burn up body tissue. As a preventive measure glucose and sodium bicarbonate are frequently given by mouth as a routine pre-operative preparation. Miscellaneous Conditions.-Normally the blood of in- fants contains 9-11 mgm. calcium and about 5 mgm. inorganic phosphorus per 100 cc. plasma. In infantile rickets and tetany these amounts are appreciably de- creased. The chlorids of blood are decreased in certain edemas, pneumonia, bichlorid poisoning, and often in diabetes. Normally the blood contains about 500 mgm. NaCl per 100 cc. blood. Cholesterol of the blood is increased in diabetes, cer- tain cases of nephritis, the latter stages of pregnancy, and in many cases of jaundice. The estimation of the hemoglobin of the blood is valu- able in determining the degree of anemia present in an individual. It follows quite closely the red blood cell count. It is a direct measure of the capacity of the blood to carry oxygen. When blood is being drawn for the determination of urea nitrogen, uric acid and sugar, the sample should be withdrawn before breakfast, as the amount of these sub- stances is affected by diet. It is the nurse's responsibility to see that a patient, wrho is to have a blood chemistry, does not have food for twelve to fourteen hours before the blood is withdrawn. When a specimen of blood is taken for a blood chemistry, it is important to know whether the serum or the whole blood is to be studied. When whole blood is desired, it must be collected in 162 APPLIED CHEMISTRY FOR NURSES sodium oxalate tubes, as the oxalate will cause the calcium in the blood to be precipitated and prevent is from func- tioning, and causing the blood to clot. When blood is col- lected for a carbon dioxid determination, in addition to the oxalate in the tube a light paraffin oil is sometimes used to prevent the escape of carbon dioxid. When whole blood is desired, a dry syringe may be used, or the blood is allowed to flow directly into the tube and mixed with the oxalate by rotating it. When there is desired the serum only, a plain sterile tube is used and the blood allowed to clot. Blood kept at room temperature for more than an hour or two deteriorates. It is especially important that the blood of diabetic patients be sent to the laboratory promptly. If the specimens are kept at room temperature they show a low percentage of sugar. The normal osmotic pressure of the blood is maintained by the salts in solution and any excess salts are excreted in the urine or in the perspiration. When it is desired to restore fluid to the body after hemorrhage, a solution of the same osmotic pressure, an isotonic solution, is used, namely, 0.9% of sodium chlorid. A solution of less osmotic pressure, a hypotonic solution, will cause the red blood cells to disintegrate. This process is known as hemolysis or laking. It may also be caused by bacteria, such as the hemolytic streptococcus, or by introducing into the blood the blood of another animal. On the other hand if the solution introduced is hypertonic, that is of greater osmotic pressure, fluid will be withdrawn from the cor- puscles and the shriveling of the corpuscles will result. The introduction of distilled water will cause hemolysis. In severe hemorrhage transfusion may be resorted to. BLOOD 163 It is important that the blood of the donor be tested before the transfusion takes place as it may cause hemol- ysis. Two main methods are used in transfusing blood, the direct transfer of the blood from the donor to the recipient, or it may be collected into paraffined tubes or into sodium citrate tubes. The collection of the blood into a tube that is coated with a smooth viscid substance, such as paraffin, prevents clotting. This same effect is had when the citrate or oxalate tubes are used. It is believed that the citrate unites with the calcium and holds it in a unionized form and it therefore does not function. When a solution is given intravenously to provide en- ergy a 5% solution of glucose is used. In acidosis, a 2% solution of sodium bicarbonate may be introduced intravenously. Outline for Study I. The Blood a. Constituents (1) Cells (2) Plasma (a) Nitrogen containing compounds (&) Inorganic salts (c) Gases (d) Other substances II. Blood chemistry in Disease a. Importance b. Kidney conditions c. Diabetes (1) Use of insulin (2) Sugar tolerance 164 APPLIED CHEMISTRY FOR NURSES d. Acidosis e. Other conditions III. Method of Obtaining Blood a. Test tubes used IV. Introducing Fluid into the Body a. Normal salt solution (1) Isotonic solution (2) Hypertonic solution (3) Hypotonic solution &. Blood transfusion c. To provide energy d. To increase alkalinity CHAPTER XVIII The Chemistry of the Tissues Supporting Tissues.-The supporting tissues consist of epithelial tissue, white and yellow connective tissue, cartilage, and osseous tissue or bone. Hair, horn, hoof, feathers, nails and the epidermal layers of the skin are all epithelial tissues. They consist mainly of the albumi- noid keratin which is a simple protein, characterized by its insolubility in water and indigestibility. This pro- tein contains a large amount of sulfur. White fibrous tissue a principal constituent of tendons contains the albuminoid, collagen, which when boiled with water is changed to gelatin, a protein suitable for body nutrition. Yellow elastic tissue, abundant in ligaments, contains the insoluble albuminoid elastin which differs from keratin in that it may be digested by alimentary enzymes. The solids of bone contain about equal parts of organic and inorganic matter. The organic portion consists mainly of albuminoids and yields some gelatin when boiled with water. The inorganic portion consists mainly of calcium carbonate and phosphate and is very constant in composition. The cement and dentine of teeth are of practically the same composition as bone. The enamel contains less water and is the hardest substance in the body. 165 166 APPLIED CHEMISTRY EOR NURSES Muscular Tissue.-Muscle tissues are divided into vol- untary or striated and involuntary or smooth muscle. More is known of the chemistry of the former. Volun- tary muscle contains about 25 per cent solids of which four fifths are proteins. The principal protein is called myosinogen. It will clot and has some of the prop- erties of a globulin. The phenomenon of rigor mortis or stiffening after death is associated with the coagulation of this protein. Muscle contains inorganic salts, some of which are associated with its irritability. Muscle contains small amounts of a large group of sub- stances which are classified as extractives. The more in- teresting are sugar, glycogen, lactic acid, fat, creatin, creatinin, urea and uric acid. Glycogen as has been men- tioned, is the source of the sugar which supplies energy for work. Lactic acid is produced from the sugar during work and may be associated with some of the symptoms of fatigue. Urea, uric acid, creatin, creatinin are prod- ucts of protein metabolism. Nervous Tissue.-Nervous tissue contains about 85 per cent water. Of the solid matter the proteins are most abundant and comprise about 50 per cent. There are three distinct proteins, two globulins and a nucleo- protein. The characteristic feature of nervous tissue is the presence of a group of lipoid or fat like substances. Lecithin is one of the better known. When broken down it yields fatty acids, glycerol, phosphoric acid and a base known as cholin. The cerebrosids contain nitrogen but no phosphorus and on hydrolysis yield a sugar. Glandular Tissues.-The Liver. The liver is the largest glandular organ of the body. At various times it has THE CHEMISTRY OF THE TISSUES 167 been associated with nearly all the metabolic processes of the body, but gradually many functions that were once only attributed to the liver are now known to be func- tions of other tissues. As has been mentioned the liver is the storehouse for the sugar of the body in the form of glycogen. The liver secretes a very important fluid, the bile. The bile is both a secretion and an excretion. As the kidneys excrete water-soluble substances so the liver excretes the fat-soluble substances as cholesterol, lecithin, and certain pigments especially the decomposition products of hemoglobin. The bile is a ropy, viscous, sub- stance with a very bitter taste. Human bile is generally brownish yellow but it may be green. It is secreted into the intestine in much larger quantities during the diges- tion of food and may be activated by some such hormone as secretin which activates the pancreas. Bile contains protein, lipoids, especially cholesterol, characteristic bile salts, and bile pigments. The protein, mucin, is mostly responsible for the ropy consistency. The two character- istic acids of the bile salts are glycocholic and taurocholic acid. The bile salts help hold the lipoids in solution and are important in aiding the enzymes in digestion. The bile pigments are mainly bilirubin and biliverdin. They are the breakdown products of the hemoglobin of the blood and are probably present in the bile as ex- cretory products. There are large quantities of cholesterol present in the bile and much of this is excreted through the intestine. Bile is excreted under low pressure and the blocking of the bile passages is quite common. The bile then backs up into the blood stream producing icterus or jaundice characterized by a yellow pigmentation of the 168 APPLIED CHEMISTRY FOR NURSES skin. The presence of bile in the blood stream is especially objectionable becanse it very readily hemolyzes the red blood cells. Mammary Glands.-Milk, the secretion of these glands, is the natural food. It is a complete food for infants and although it lacks a few inorganic salts it is very satis- factory for adults. Its composition varies somewhat with the species and it is for this reason that it is necessary to modify cow's milk for infant feeding. The accompany- ing table gives the approximate composition of human milk and shows how other varieties vary. In this table is given the approximate number of days that it takes for the young of the species to double its weight. There is an interesting relation here between the composition of the milk of the mother and the growth of the young. A faster growing animal requires more protein, fat and salts and less sugar. Besides the protein, casein, there are also present in milk smaller amounts of albumin and globulin. The fat of milk, butter, is characterized by the presence of lower fatty acids than are found in other animal fats. The sugar present is lactose but other sugars have been found equally efficient for substitution in infant feeding. Of the necessary inorganic salts milk is low in iron but this has been supplied to the fetus by the mother. The excess of inorganic salts in cow's milk may be the cause of the formation of large curds when this milk is used for infant feeding. Boiling the milk reduces the size of the curds as do lime water and sodium bicarbonate. Colostrum is the name given to the milk secreted for a short time after parturition. It contains more solids and THE CHEMISTRY OF THE TISSUES 169 Period for young Protein Fat Sugar Inorganic Solids to double weight Salts % Animal -days- % % % % Human 180 1.4 3.5 7.0 .2 12.8 Cow 47 3.5 3.6 5.0 .7 12.6 Goat 22 3.7 4.0 5.0 .8 10.2 Sheep 15 5.0 4.0 5.4 .8 • . • Cat 10 10.0 10.0 3.4 1.0 • • • Rabbit 6 11.0 12.0 1.8 2.5 • • • 170 APPLIED CHEMISTRY EOR NURSES a larger amount of a globulin which seems quite essential to the welfare of the newborn. Glands of Internal Secretion.-There are a number of glandular organs in the body whose excretions have very important regulatory actions. Their excretions do not pass through any ducts but are apparently poured di- rectly into the blood stream. Among these organs the adrenals, or supra-renals, thyroid, pancreas, parathyroid, ovaries, testes, pituitary or hypophysis, thymus, and pineal are the most important. These organs are also called the endocrine or cryptorrhetic glands. The adrenals are small bodies situated on the upper poles of the kidneys. The cortex apparently excretes an unknown substance which is very essential to life. The medulla excretes a well known and important medicinal generally known as adrenalin. This has the important function when injected into the body of greatly in- creasing blood pressure by constriction of the capillaries. Because of its action in constricting capillaries it has found valuable use in surgery in restricting the blood supply thus giving a comparatively bloodless area. It has been isolated and the chemical structure is known. The pituitary is about the size of a pea and lies at the base of the brain. One portion of the pituitary secretes a substance generally known as pituitrin or hypophysin. It has an action on the blood pressure similar to adrenalin except that it persists for a longer time. It is also used in obstetrics for the contraction of the uterus as it has a de- cided action on smooth muscle. Another portion of the pituitary is associated with the growth of the bony struc- THE CHEMISTRY OF THE TISSUES 171 ture of the body. In gigantism and acromegaly, this por- tion of the pituitary is involved. The thyroid is a small highly vascular gland situated in the neck. The active principle of this gland has been isolated and identified chemically. It is known as thy- roxin. It is associated with the general body metabolism. An excess of thyroxin acts as a whip and burns more of the body material than normally. Goiter is associated with an over-functioning or growth of this gland. If the gland fails to develop early in life a cretin or dwarf is the result. Removal or atrophy of the gland in adult produces myxodema. Thyroid extract is given to counter- act these conditions. Besides the excretion which the pancreas pours into the intestine it has another very important internal secretion which apparently is entirely independent of the external. It is associated with the metabolism of sugars and fats in the body. The substance has been recently isolated from the pancreas and is known as insulin. The parathyroids are either embedded in the thyroid or lie close to it. The complete removal of the parathyroid tissue causes tetany and death. The active principle is unknown. They are also associated with the calcium metabolism of the body. The active principles of the testes and ovaries have not been isolated. Their secretion is very important in de- termination of sex function and characteristics. The spleen and bone marrow are mentioned here be- cause of their important function in the formation of new red blood cells. It may be possible that the spleen has 172 APPLIED CHEMISTRY FOR NURSES an internal secretion. Less is known of the action of the thymus and pineal glands. Outline for Study I. Supporting Tissues a. Albuminoids present b. Inorganic matter II. Muscles a. Myosinogen b. Cause of rigor mortis c. Extractives III. Nervous Tissue a. Proteins b. Fat-like substances IV. Glandular Tissues a. Liver b. Mammary Glands (1) Comparison of human milk with other varieties V. Internal Secretions a. Endocrin glands b. Adrenalin c. Pituitrin d. Thyroxin CHAPTER XIX The Excretions of the Body After the body has absorbed food products from the ali- mentary canal and each cell has made use of these prod- ucts for its energy, maintenance and growth, the end- products and unused material must be excreted from the body. When carbon is oxidized to carbon dioxid the majority of this, as we have seen, passes through the blood stream as sodium bicarbonate and is released in the lungs and expelled from the body. The water from the oxida- tion of hydrogen and from the intake through the mouth is excreted through four channels, the feces, the skin, the lungs and the kidneys. At first thought we might believe that a majority of this water passed through the kidneys, but normally about an equal amount passes through the lungs and skin and during hard labor this is greatly in- creased. The urine excreted in the summer is normally much less than in the winter because of the greater loss of water through the skin. As an excretory organ from the body proper the in- testine is relatively unimportant. The excretory products of the liver and some inorganic salts of iron and calcium normally leave the body through the intestine. The skin besides taking out relatively a large amount 173 174 APPLIED CHEMISTRY FOR NURSES of water does excrete some nitrogen containing products as urea, also some inorganic salts. The benefit of hot packs and hot baths to reduce edema and to aid slightly in the elimination of nitrogenous waste is evident. The kidney is the main organ for the excretion of a variety of substances especially nitrogen containing and inorganic salts. Normal urine varies in color from light straw to amber, but the color is affected by diet, drugs and disease. It has a characteristic odor, is acid in reaction and has a specific gravity of from 1.010 to 1.020. An adult secretes normally 600-1500 cc. in twenty-four hours. The adult body does not store nitrogen as it does fats and carbo- hydrates. This nitrogen must be excreted from the body and about 90 per cent of this normally passes through the kidney. About 85 per cent of the nitrogen in the urine is in the form of urea, the end-product of protein metabolism. 5-10 per cent is ammonia nitrogen. The ammonia is apparently formed in the kidney. It may be greatly increased at the expense of the urea nitrogen in certain forms of acidosis as diabetic acidosis. In nephritic acidosis the kidney seems unable to form ammonia. In the digestion and oxidation of protein material phosphates and sulfates are formed. These are excreted through the kidney. The phosphates are excreted as the acid salts and are known as buffer salts because they are able to carry out acid and base combined in the molecule in such a form that true acidity or alkalinity is much decreased. A urine is always acid in reaction when the subject is on an ordinary mixed diet which contains an excess of acid forming substances over base forming substances. THE EXCRETIONS OF THE BODY 175 The chlorids in the urine depend almost entirely on the chlorids in the diet. Urinalysis.-The chemical analysis of the urine in dis- ease reveals certain facts useful in clinical diagnosis. We have already noted that when kidney tissue has been damaged it becomes permeable to albumen. The presence of albumen in the urine, however, does not always indicate the destruction of kidney cells but there may be a temporary inability of the kidney to function prop- erly as in febrile conditions when it is compelled to remove a large amount of toxic material from the body. The presence of a reducing sugar points towards diabetes, but it is not as valuable an index as the blood sugar. If there is diabetic acidosis the so called acetone bodies are present in the urine. Diuresis or an excessive amount of water in the urine is characteristic of diabetes because water is required to excrete sugar. Polyuria is also char- acteristic of chronic nephritis, especially large night urines as the kidney is unable to excrete concentrated urines. The specific gravity is a routine examination of the urine but gives little information. Much sugar in the urine gives a high specific gravity. The bile salts and pigments are present in the urine under certain patho- logical conditions and may be easily recognized chemi- cally. When putrefaction of protein takes place in the intes- tines we have learned that indol is produced. When it is absorbed, it is conjugated, probably in the liver, to a less toxic substance, indican. A trace of indican is present in normal urine but not sufficient usually to react to chemical test. Where there is severe putrefaction or in any disease 176 APPLIED CHEMISTRY FOR NURSES where there is intestinal obstruction, or a large amount of exudates, as in empyema, the urine gives the test for in- dican. Blood occasionally appears in the urine especially from lesions in the kidney or urinary tract. It is recognized by certain color tests. In mercury, lead, and arsenic poisoning small amounts of the salts appear in the urine and may be tested for chemically as an aid to clinical diagnosis. Unorganized sediments separate from urine of which the calcium salts, phosphates, and urates are the most important. The examination of the organized sedi- ments is entirely by the microscope. They include epi- thelial cells, pus cells, casts, mucus, blood. Urine to be examined must be fresh. It should be collected in domestically clean utensils, protected by a cotton plug or a paper cover from the air and kept in a cool place. It may have a few drops of chloroform, toluol, or formalin added to it to preserve it. Any aldehyd will reduce Fehling's Solution as will chloroform, a fact which it is important to remember when collecting urine from a diabetic patient. Urine which smells of ammonia has decomposed and is of no use for analysis. Urine which is allowed to stand also becomes alkaline. Functional Tests.-There are several important func- tional kidney tests. In the phenolsulphonephthalein test, a cc. of a solution of phenolsulphonephthalein is in- jected into the lumbar muscles, the patient having pre- viously emptied the bladder. The urine is voided in one hour samples. The quantity is noted each time, and a solution of sodium hydroxid is added drop by drop to bring out the maximum color since phenol- THE EXCRETIONS OF THE BODY 177 sulphonephthalein assumes a pink color in the presence of alkali. Each sample of urine is diluted to a definite volume with distilled water and comparison is made with a standard solution. This dye is used because it is non- toxic, it is eliminated almost entirely by the kidney, and it appears in the urine about ten minutes after it is injected. In the Mosenthal test, the patient is given specially prepared meals in which no salt has been used but a certain amount of salt is given with the meal. This is a twenty-four hour test, and the urine must be col- lected every two hours. The urine is tested for sodium chlorid and urea. The retention of salt is an indication that the kidneys are not functioning properly. Kidney Stones.-The inorganic salts in the urine are of little consequence but we have seen in our study that salts may be precipitated by chemical change. When there is an excess of salts in the urine or an excessive acidity or alkalinity which may precipitate them, there may be the formation of kidney stones. These kidney stones upon analysis show that they are composed of precipitated salts, mucus, cells, etc. The nucleus may be bacteria. Outline for Study I. Excretory organs a. Intestines b. Skin II. The Kidneys a. Function b. Normal urine c. Nitrogenous waste 178 APPLIED CHEMISTRY FOR NURSES d. Significance of Albumen Sugar Indican Acetone Polyuria e. Functional tests f. Kidney stones REVIEW QUESTIONS Physical and Chemical Changes 1. Define chemistry. 2. Why should a nurse study chemistry ? 3. How can you change the physical state of substances and give examples. 4. Define condensation, distillation, melting point, sub- limation, freezing point. 5. How does chemical change differ from physical change and give examples of each. 6. What may be the effect of heating metals in the air? 7. What is a precipitate ? 8. Why is it a safe rule never to give two drugs to- gether unless so ordered ? Elements, Compounds and Mixtures 1. Name ten elements found in the body either free or in compounds and give their symbols. 2. What are the symbols for sodium, sulfur, silver, copper, carbon, potassium, chlorin, iodin, hydrogen, nitro- gen, oxygen, bromin, mercury, calcium, iron ? 3. What is an atom, a molecule, a symbol, a formula, a chemical equation? 4. What is an element ? a compound ? a mixture ? How do we distinguish between the last two ? Give examples. 179 180 APPLIED CHEMISTRY FOR NURSES 5. What is the atomic theory? 6. Define residue, filtrate, constituent, component. 7. How does the law of definite proportions apply in making a cake ? 8. Give the various types of chemical change with an example of each. 9. What is the law of the Conservation of Matter? 10. Mark the valence of the elements or radicals in the following formulas. H2S, CO2, NaCl, CH4, H2SO4, HC1, HN03, NH4C1. 11. What is the law of the Conservation of Energy? 12. Why do we use coal for fuel ? 13. What is chemical energy ? Give some common ex- amples of chemical energy being changed to some other form. 14. How is heat measured ? Oxygen and Oxidation 1. What are the physical and chemical properties of oxygen ? 2. How do we prepare oxygen in the laboratory ? How is the oxygen collected ? 3. What is a catalytic agent ? 4. What do you mean by oxidation ? Give an example of oxidation in the body. 5. How can you account for the temperature of the body ? 6. Trace the oxygen taken in by the lungs in its course through the body. 7. Explain spontaneous combustion. 8. What are the essentials for combustion? REVIEW QUESTIONS 181 9. What do you mean by kindling temperature? 10. What are the uses of oxygen ? 11. Why is oxygen ordered for patients? 12. Why do we give oxygen as an antidote for illumi- nating gas poisoning? 13. Define oxid, reducing agent, oxidizing agent, allo- tropic forms. 14. What is ozone? Hydrogen and Its Oxids 1. What are the physical and chemical characteristics of hydrogen ? 2. How is hydrogen obtained for use in the laboratory ? 3. What is the expected action of metals above hydro- gen in activity with acid ? Examples. 4. What is the expected action of metals above hydro- gen in activity with water? Examples. 5. What is hydrogenation? 6. What is the chief value in using hydrogen peroxid in a wound ? 7. Why is it important to keep hydrogen peroxid in dark bottle in a cool place ? 8. Why does hydrogen peroxid effervesce when put on a wound ? The Kinetic Molecular Hypothesis THE GAS LAWS 1. What is kinetic-molecular hypothesis ? 2. Why is it possible for us to supply patients with oxygen from a tank ? 182 APPLIED CHEMISTRY FOR NURSES 3. What is Boyle's Law ? Charles's Law ? Avogadro's Hypothesis ? 4. Why do we plug a flask of solution with cotton rather than use a cork stopper before sterilizing? 5. Why does the odor of a gas quickly permeate a room ? Water 1. Why is the autoclave very efficient for sterilization ? 2. What is the advantage of distilled water ? 3. What types of impurities are found in water ? 4. What are the conditions which determine the solu- bility of gases in liquid, liquid in liquid, solid in liquid? 5. What is the difference between unsaturated, satu- rated and supersaturated solutions? 6. Define suspension, emulsion, filtrate, colloid, solu- tion. 7. What are the colloidal solutions used in infant feeding ? 8. What is the meaning of "osmotic pressure" ? 9. Explain the reason why prunes swell when soaked in water. 10. What would happen if distilled water were intro- duced into a vein ? Explain. Electrolysis, Ionization, Acids 1. Define an electrolyte. 2. What is ionization ? 3. Account for the change in the boiling point of water to which sugar has been added ? To which table salt has been added ? REVIEW QUESTIONS 183 4. Give the composition of inorganic acids, and give their common characteristics. To what are these char- acteristics due? 5. Give three tests for an acid. 6. Why should surgical instruments be kept away from contact with acids ? 7. What acid is found in the stomach ? What is its action ? 8. If you spilled acid on a marble sink what reaction would take place? Give two other instances in which a similar reaction takes place. 9. Why is it important to keep efferverscing powders in a dry place? 10. What is the difference between a strong acid and a w'eak acid ? 11. Give the formula for hydrochloric acid, sulfuric acid, nitric acid, boric acid, phosphoric acid. Bases 1. Give the composition of inorganic bases and their common characteristics. To what are these characteristics due ? 2. Give three tests for a base. 3. Why should a strong alkaline soap not be used in washing baby clothes ? 4. How would you test for free alkali in soap or soap powder ? 5. Why is sodium bicarbonate given to counteract acidity ? 6. If a child swallowed lye, what first aid treatment would you give him ? Why ? 184 APPLIED CHEMISTRY FOR NURSES 1. Define acid oxid, basic oxid and give examples. 8. Why is magnesium oxid given as an alkali ? 9. Give the chemistry of fumigation by sulfur. 10. Give the formula for sodium hydroxid, potassium hydroxid, calcium hydroxid, ammonium hydroxid and give their "household" names. Inorganic Salts 1. What is a salt ? 2. What chemical acts will give a salt as a product? 3. Why do salts not have common properties ? 4. What do you mean by neutralization ? Give ex- amples. 5. Why should a nurse be extremely careful in clean- ing an irrigating can which is used both for normal salt irrigations and silver nitrate irrigations ? 6. What is an acid salt? A basic salt? Name one of each used in the hospital. 7. Account for the fact that when sodium bicarbonate is dissolved in water the solution gives an alkaline reaction. 8. What is the difference between gypsum and plaster of Paris and explain the use of the latter in plaster casts ? 9. Why is it necessary to watch the circulation of a patient who has had a plaster cast applied ? 10. Define efflorescent substance, deliquescent substance, hydrate, anhydrous substance. 11. What practical application can you make of your knowledge of efflorescence and deliquescence ? 12. How can you soften temporary hard water ? Perma- nent hard water? Upon what facts does this softening depend ? REVIEW QUESTIONS 185 13. Give the formulas for the following-sodium chlo- rid; hydrochloric acid; potassium bromid; silver nitrate; sulfuric acid; potassium iodid; sodium bromid, sodium bicarbonate, ammonium chlorid, mercuric chlorid, mer- curous chlorid, nitric acid, carbon dioxid, magnesium sulfate. 14. How could you test for a chlorid, a sulfate? 15. Give the chemical names and formulas for epsom salts, calomel, washing soda, saleratus. Common Metals and Their Compounds 1. What are three practical considerations with regard to metals ? 2. Give the chemistry involved when bottles of lime water are left without stoppers. 3. Why may barium sulfate be given to patients before an X-ray study? 4. What do you mean by radium emanations ? 5. Why are instruments nickel-plated ? 6. What is the difference between mercuric chlorid and mercurous chlorid ? 7. Why do silver articles tarnish ? 8. Give one fact about zinc oxid which has a practical application in your own work. 9. What is "lead water" ? 10. Why can we use a platinum wire as a transfer needle in Bacteriology? 11. Why are metal polishes advertised as containing "no acid" ? 186 APPLIED CHEMISTRY FOR NURSES Important Non-Metals and Their Compounds 1. Why is nitrogen so important an element ? 2. Account for the odor of ammonia in urine. 3. Why is it important to keep solutions of nitrates well stoppered? 4. What is the action of nitrites in the body? 5. How do bacteria make nitrogen available for plant life? 6. What practical points should be remembered when using nitric acid ? 7. What are the halogens ? 8. What are the uses of chlorin ? 9. Why is chlorid of lime used as a disinfectant ? 10. Explain the action of chlorin used as a bleaching agent. 11. Give the uses of iodin and its compounds. 12. How can you remove tincture of iodin stains from linen ? 13. What important fact should you remember with regard to iodin compounds ? 14. Give a test for iodin. 15. What is glass ? Why is it necessary to use good grade glassware for sterilizing flasks ? 16. Why is boric acid a mild antiseptic? Carbon and Its Oxids 1. What are the free forms of carbon ? 2. What is the source of Nature's supply of carbon dioxid ? REVIEW QUESTIONS 187 3. Give the common uses of carbon dioxid. 4. Give the various methods used in cooking for obtain- ing carbon dioxid ? 5. What are the conditions which give carbon monoxid as a product ? 6. Why is carbon monoxid poisoning so serious ? Organic Chemistry 1. What do you mean by organic chemistry ? 2. What is a structural formula? An isomer? 3. Name three important hydrocarbons. 4. Name and give the formula for four gases of the paraffin series. 5. What is the characteristic formula group of the al- cohols, the aldehyds, the organic acids? 6. Give the formulas for ethyl alcohol, methyl alcohol, glycerin. 7. Give a test for ethyl alcohol. 8. What are the uses of formaldehyd ? 9. How would you test milk to find out whether for- maldehyd had been used as a preservative? 10. Name five organic acids. 11. What is an ester? 12. What is the common name for phenol? What are its uses? 13. What do you mean by a "coal tar product" ? 14. What are some of the important products used in medicine which are obtained by the destructive distilla- tion of coal and wood ? 15. What are some of the important products obtained by substituting the halogens? 188 APPLIED CHEMISTRY FOR NURSES 1G. Name two classes of nitrogen containing com- pounds. 17. What is an alkaloid ? The Chemistry of Foods 1. What are the elements found in carbohydrates? Classify carbohydrates. 2. What is Fehling's test for reducing sugars and on what fact does it depend ? 3. How could you differentiate between glucose and lactose ? 4. Give the carbon cycle and the law which it illus- trates. 5. What elements are present in proteins ? 6. Classify the proteins. 7. What can you say about the solubility of the simple proteins ? 8. How may proteins be precipitated ? 9. Why is bichlorid of mercury inefficient for disin- fecting excreta ? 10. Give in detail two color tests for protein. 11. What is fat? 12. What is saponification? 13. How do we obtain soap? Give the reaction. 14. Why does soap cleanse ? 15. How are soaps formed in the body? 16. What is formed when soap is used with hard water ? 17. How can you distinguish butter from oleomar- garine ? REVIEW QUESTIONS 189 18. What is the importance of inorganic salts in the diet ?' 19. What are vitamins ? 20. What are the essentials of a complete diet? Digestion 1. What is an enzyme? Give its characteristics. 2. Name the enzymes of the saliva, gastric juice, pan- creatic juice and intestinal juice. 3. What foodstuffs are chemically acted upon in the mouth ? The stomach ? The intestines ? 4. Give the hydrolysis of starch in the body. 5. Give the hydrolysis of protein in the body. 6. How may fats be hydrolyzed ? Give the hydrolysis in the body. 7. Why is fat restricted in the diet of a patient with jaundice ? 8. What do you mean by a "soap stool" ? 9. Why is it important to "force fluids" in conditions in which diarrhea is present ? 10. How could you prevent excoriated buttucks in chil- dren with carbohydrate indigestion? Metabolism 1. Define metabolism. 2. How do the food products get into the blood stream ? 3. How is protein metabolized ? 4. What is urea? 5. What happens to the glucose which is absorbed from the intestines? To the fats? 190 APPLIED CHEMISTRY FOR NURSES 6. What is a bomb calorimeter ? 7. If a food contained six grams of protein, eight grams of fat, four grams of carbohydrate, how many calories of heat would be furnished by its oxidation ? 8. What is the basal metabolic rate of an individual ? 9. How do you prepare a patient for a basal metabolic test ? The Blood 1. What are the functions of the blood? 2. What are the main proteins present in the plasma. 3. Why should blood stained linen be soaked in cold water ? 4. What are the principal inorganic salts of the plasma and what are their functions ? 5. What would a blood chemistry reveal in a severe nephritis ? 6. Why is sugar not found in the urine of a normal person ? 7. How is a patient's sugar tolerance determined ? 8. Why is acidosis frequently associated with diabetes ? 9. Account for the decrease in the alkalinity of the blood in acidosis. 10. What are the practical considerations which a nurse must remember when blood is to be withdrawn for a blood chemistry ? 11. Define isotonic, hypertonic and hypotonic solu- tions. 12. Why is it important that normal salt solution in- troduced into the blood stream be of the proper osmotic pressure ? REVIEW QUESTIONS 191 13. Why are sodium citrate tubes used in a blood trans- fusion ? The Chemistry of the Tissues 1. What are the three albuminoids present in support- ing tissue? 2. What causes "rigor mortis ?" 3. What substances are found in muscles ? 4. Give two functions of the liver. 5. What substances are present in the bile ? 6. What is the effect of bile in the blood stream ? 7. Give the composition of human milk. 8. Give in detail why it is necessary to modify cow's milk for infants? 9. Name three internal secretions and give their action in the body. 10. What is insulin ? The Excretions 1. How are the end products of metabolism excreted by the body ? 2. Give the composition of normal urine. 3. In what compounds do we find nitrogen in the urine ? 4. What is the source of the indican in urine and how may you test for it ? 5. How is phenolsulfonephthalein used in a kidney functional test? 6. How would you preserve a specimen of urine from a diabetic patient ? 7. What kind of sugar is found in the urine of a dia- betic patient? How would you test for it? 192 APPLIED CHEMISTRY FOR NURSES 8. Give the test for albumen in urine and explain the underlying chemistry. 9. What are kidney stones ? 10. Why is it important that urine be examined while fresh ? LABORATORY MANUAL Chapter 1 Exercise 1. Preliminary. Learn to bend glass tubing, break glass with a file, fold filter papers. To get the idea of capacity measure 5 cc. water into one test tube and 10 cc. into another. Practice the above after demonstration by instructor. Exercise 2. Physical and Chemical Change. Platinum. Examine a platinum wire noting its physical characteristics. Hold the wire in the flame of a Bunsen burner. What happens? Remove from the flame and when cold compare its properties with those first noted. Is there any permanent change? Classify as physical or chemical any change observed in the wire under the influence of heat. Magnesium. With forceps hold a piece of magnesium ribbon in the flame. Examine the product and compare its properties with those of the magnesium ribbon. Classify the change which has taken place and give reasons for your conclusion. lodin. Put several crystals of iodin in a dry test tube and gently heat the bottom of the tube. What happens? Remove from the flame and examine the sides of the test tube. Heat again. Has the iodine crystal been changed, if so, what caused the change ? Classify the change. Exercise 3. Compounds. Note the physical characteristics of sugar. Put a layer of sugar about half an inch thick into a dry test tube. Hold the test tube in the flame until no further change takes place. What do you see on the sides of the tube ? After the tube has 193 194 APPLIED CHEMISTRY FOR NURSES cooled break it m a mortar and examine its contents as to color, taste and solubility in water. How does chemical change differ from physical change? Give examples of each. Chapter 2 Exercise 4. Mixtures and Compounds. Put a spatulaful of sand and one of salt in a dry mortar. Mix thoroughly. Place in a test tube, and add a little water. What happens? Filter (Figure 1), and collect the filtrate in an evaporating dish. Place the evaporating dish on a wire gauze on a tripod, heat, until the water evaporates. Taste the substance that remains. Con- clusion. Put a spatulaful of powdered sulfur and a little smaller quantity of iron powder in a dry mortar. Grind thor- oughly with a pestle. Divide in three parts and test the resulting material as follows: 1. Sprinkle one part of it on a sheet of white paper and examine with a lens. State to which class, mixture or com- pound this belongs. 2. Kun a magnet across the underside of the paper. Can you separate practically all of the iron from the sulfur? Does this confirm your conclusion in 1 ? 3. Place a portion in a test tube, add about 5 cc. of hydrochloric acid. Shake and warm. Is the entire sub- stance acted upon? 4. Place the remainder of the substance in a dry test tube and carefully heat in the flame of the Bunsen burner until a striking change takes place. When the glow first appears, remove from the flame and observe carefully. Let it cool, break the tube in a towel, remove the contents, put it in a mortar and grind. Bepeat the tests tried before. Has the heat caused any change? Beason? To what class of matter does this belong? What was taking place when the glow appeared? Fig. 1. LABORATORY MANUAL 195 Which contains the larger amount of chemical energy ? Give several examples of mixtures, compounds and elements. Give three ways of distinguishing a mixture from a com- pound. Exercise 5. Problems. Zn + 2HC1 = H2 + ZnCl2 Zinc 4- hydrochloric acid = hydrogen -|- zinc chlorid Atomic weights: H = 1, Zn = 65, 01 = 35.5. How many grams hydrogen will be formed when hydro- chloric acid acts on 10 gm. zinc? Since the molecular weight of zinc chlorid is 136 and the atomic weight of zinc is 65 what per cent zinc does zinc chlorid contain ? Exercise 6. Types of Chemical Change. Burn some sulfur in the air. What is the odor ? What type of chemical change is this ? In a test tube place a small amount of red mercuric oxid. Heat it. Note the globules of mercury on the wall of the tube. What type of chemical change is this? To a test tube add 5 cc., dilute HC1 and some iron filings. Warm and note the formation of bubbles of gas. What gas is this? What became of the iron? What type of chemical change is this ? Put 10 cc. of normal salt solution in a test tube and add two or three drops of silver nitrate solution. What is the precipitate? What remains in solution? What type of chemical change is this? Chapter 3 Exercise 7. Preparation and Properties of Oxygen. From Potassium Chlorate (KC103). Heat a small quan- tity of crystallized potassium chlorate in a test tube. Calcu- late the time necessary to obtain the oxygen freely. When the gas is being given off freely, bring a glowing splinter of wood to the mouth of the tube. Explain the result. Heat 196 APPLIED CHEMISTRY FOR NURSES an equal amount of manganese dioxid for the same length of time. Is oxygen set free? From Potassium Chlorate and Manganese Dioxid. Put a small quantity of potassium chlorate crystals and an equal quantity of powdered manganese dioxid in a hard glass test tube. Heat and test as before. From which substance was the oxygen set free? Give a reason for your answer. What effect does the manganese dioxid have? What is the technical name for this action? Set up the apparatus as indicated. Weigh out 10 grams of potassium chlorate and 5 grams of manganese dioxid. Mix them thoroughly and pour into a hard glass test tube. Cover with a loose plug of shredded asbestos or glass wool. Insert the stopper with its tubes and clamp to the ring stand. Fill a basin with water. Fill the bottles with water. Cover each with a glass plate and invert them into the basin. Re- move the glass plate and adjust the delivery tube under the bottle. Heat the length of the test tube gently with a small flame. When the first bottle of gas is full remove and cover it with a glass plate and slip another bottle in place. Collect 3 bottles of gas. Whenever the flame is withdrawn remove the end of the delivery tube from the water. Dip a glowing splinter into one bottle and observe what happens. Remove the splinter and repeat as many times as possible. Does the gas burn? How does the glowing splinter change? What property of oxygen does this show? Put a small piece of sulfur in a deflagrating spoon and hold it in the flame until the sulfur ignites. Lower the spoon into a bottle of oxygen. Describe the change in the flame. Hold a piece of charcoal in the flame long enough to have it glow faintly and then lower it into the bottle of oxygen. What are the resulting products when the sulfur and charcoal are burned ? What are the physical properties of oxygen ? Fig. 2. LABORATORY MANUAL 197 What are the chemical properties of oxygen ? In what state is oxygen in the air ? Why is heat used to separate oxygen from its compound ? Exercise 8. Oxidation and Reduction. Immerse the fingers in potassium permanganate solution and leave them until they are stained a brown color. Now immerse the fingers in a solution of oxalic acid, and wash until the stain is removed. The oxalic acid has reduced the permanganate stain to a colorless solution. The oxalic acid has been oxidized. This method may be used in sterilization of the hands. Chapter 4 Exercise 9. Preparation and Properties of Hydrogen. Make sure that your fingers are dry, then wrap a small piece of sodium no larger than a small pea, in a dry piece of filter paper in such a form that it will pass easily through the mouth of a test tube. Fill a test tube with water and invert it in a beaker of water. Raise the test tube until its mouth is within % inch of the surface of the water, incline the tube slightly and with pincers place the filter paper con- taining the sodium quickly in the mouth of the tube and release it. What happens ? If the test tube is not filled with gas, put in a second piece of sodium in the same way. Test the gas evolved with a lighted taper. Test the solution in the beaker with litmus paper and by rubbing it between the fingers. In a test tube place 5 cc. of dilute HC1 and add a piece of zinc. Soon bubbles of a gas form. What is the gas? After the gas has generated for a minute place the mouth of the test tube to a flame. What reaction took place? What are the chemical properties of hydrogen? What are the physical properties ? Exercise 10. Hydrogen Peroxid. Heat 5 cc. of hydrogen peroxid in a test tube and test the gas with a glowing splinter. To another 5 cc. portion add a 198 APPLIED CHEMISTRY FOR NURSES little manganese dioxid at room temperature and test the gas as before. What is the action of hydrogen peroxid in a wound? Does the blood or tissue play any part in the reaction. Test for hydrogen peroxid: To half a test tube of water add ten drops of hydrochloric acid, enough of potassium dichromate solution to give a brick red color, a layer of ether, and finally a few drops of the solution to be tested. If hydro- gen peroxid is present the layer of ether will become blue. Chapter 5 Exercise 11. Diffusion of Gases. Into one test tube place a few drops of concentrated hydro- chloric acid. Into another test tube place a few drops of con- centrated ammonium hydroxid. With one in each hand warm gently over the flame. Now place the mouths of the test tubes close together. The gases mix by diffusion and a chem- ical reaction takes place. What is formed? Could you tell which gas is the heavier? Exercise 13. Diffusion in a Liquid. Into a test tube full of water drop a few crystals of potas- sium permanganate without any agitation of the liquid. Note the pink streaks in the liquid where the permanganate has gone into solution. Allow to stand a few minutes and note that the streaks have disappeared and the pink color has mixed with the water. Allow to stand in your desk for a day or so without any agitation of the liquid. Note the gradual diffusion upwards of the stronger permanganate solu- tion in the bottom of the tube. Could this happen if the molecules were not in motion ? Chapter 6 Exercise 13. Purification of Water. To a 500 cc. flask add about 50 cc. water, a few crystals of potassium permanganate and some ordinary table salt. LABORATORY MANUAL 199 Use a Liebig condensing tube if possible or set up an ap- paratus as indicated in figure. Boil the water over a flame and note the distillate as it collects and drops from the tube. Is it colored? Taste a drop of the distillate. Does it taste salty ? What would you say about the purity of the distilled water ? The salt and the colored permanga- nate represent impuri- ties. Would you say that the distillate con- tained any bacteria? Exercise 14. Distribution of Water. In dry cool test tubes place successively, a small piece of wood, a piece of cracker, raw meat, any fresh vegetable and heat the substance in the lower end of the test tube. If water is present it will condense in small droplets on the upper cold portion of the tube. How many of these substances con- tain water? What general conclusion would you draw con- cerning the general distribution of water ? Exercise 15. Solubility. Gases, (a) Warm a little faucet water in a test tube but do not heat to boiling. What is the evidence of a gas dissolved in the water? What effect does heat have? (b) Warm slightly a few cc. of ammonium hydroxid in a test tube. Is ammonia gas more or less soluble than air in water ? Does the increase of temperature make the gas more or less soluble? Liquids. Precaution. Alcohol and ether are inflam- mable. To separate test tubes half full of water add (a) a few drops of olive oil, (b) 1-2 cc. ether, (c) 2-5 cc. alcohol. Shake and note which are soluble. To 2-3 cc. ether add a few drops of olive oil and shake. To 2-3 cc. alcohol add Fig. 3. 200 APPLIED CHEMISTRY FOR NURSES 1-2 cc. ether. Shake. Prepare a small table of the solu- bilities as you have found them. Solids, (a) Weight on separate filter papers three grams each of sodium chlorid, potassium chlorate, and barium sul- fate, potassium nitrate, solid sodium hydroxid and zinc oxid. Add one-third of the sodium chlorid to 10 cc. of water in a test tube and shake vigorously. If the substance dissolves, add another third, and if that dissolves, add still another third. Repeat this process with each of the other substances. The potassium chlorate should be powdered before using. Save the potassium chlorate solution for experiment (b). If the first gram of any substance fails to dissolve com- pletely, filter the liquid and evaporate the filtrate. Why? What is here shown about the solubility of solids ? Is there any evidence of "heat of solution"? Positive or negative? (b) Pour the saturated solution of potassium chlorate ob- tained in (a) into a beaker and heat, but do not boil it. Now add gradually more potassium chlorate and stir until the solu- tion becomes saturated at this temperature. Let the solution cool. Result. Try the solubility of iodine crystals in water, in alcohol. Exercise 16. Dissolved Salts and Boiling Point. Fit a small flask with a two-holed stopper. Insert a thermometer in one hole and leave the other open. Place about 100 cc. of water in the flask. Insert the stopper and place the thermometer so that part of the bulb at least is in the water. Heat the water to boiling and note the boiling point of water. Remove the flame and add 10 gm. NaCl. Determine again the boiling point of the solution. Has it changed? What does the dissolved salt do to the boiling point ? Exercise 17. Osmotic Pressure. To one test tube add about 10 cc. distilled water and to another about 10 cc. "normal saline" (0.9 per cent sodium chlorid). To each add a drop of blood and mix. Note in the one tube the clear solution of a brownish red color and in LABORATORY MANUAL 201 the other the turbid suspension of red blood cells. In one tube the cells were entirely ruptured. What is this called? What was the force that ruptured the cells? Chapters 7 and 8 Exercise 18. Acids. For the following tests use the dilute (about 10 per cent) solutions of nitric, hydrochloric, sulfuric, and tartaric acids. a. Taste: Dilute 1 cc. of each acid solution in a clean test tube to 10 cc. Use a clean glass rod and taste each acid. What common characteristic do you note? b. Indicators: 1. Put strips of red and blue litmus paper on a watch glass. With a glass rod put a drop of each acid solution on the two litmus papers. 2. Add a drop of methyl orange solution to 2-5 cc. of each acid. Repeat using phenolphthalein as the indicator. Record your observations. c. Interaction of Metals with Acids. Try the action of dilute hydrochloric, sulfuric, and tartaric acids on a small quantity of iron filings. It is necessary to heat the tartaric acid slightly. Test the gas by holding a lighted splinter near the mouth. What is the gas? How would you show that it did not come from the water ? Could you suggest why the tartaric acid did not react as readily as the other acids? Write equations for the action of the hydrochloric and sul- furic acids. (Figure 4.) d. Action of acids with carbonates: In test tubes try the action of each acid on marble (CaCO3). Fit the test tube with a one-hole rubber stopper and with a delivery tube pass the gas evolved through a small quantity of lime water (Ca (0H)2). The formation of a white precipitate (CaCO3) is a test for carbon dioxid. Write all reaction equations. Bases. Use 5-10 per cent solutions of sodium, potassium, and ammonium hydroxids and a saturated solution of calcium hydroxid. Fig. 4. 202 APPLIED CHEMISTRY FOR NURSES (a) Taste: Dilute 1 co. of each of the first three solu- tions to 10 cc. in a clean test tube. Taste a drop of each. Taste the calcium hydroxide solution without diluting. Is there any common characteristic to the taste ? (b) Test each base with: 1. Pink litmus paper. 2. Methyl orange. 3. Phenolphthalein. Record results. Test for Free Alkali in Soap and Soap Powder. Dis- solve a little of the soap to be tested in about 5 cc. alcohol. Add 5 cc. water and mix. Add a few drops of phenolphthalein. A pink color indicates the presence of free alkali. Test the following products by the use of litmus paper and determine whether they are acid or alkalin in reaction: orange juice, lemon juice, sweet milk, sour milk, borax, vinegar, milk of magnesia, lime water. What ions must be present to give the acid and alkalin reaction? Exercise 19. Acid and Basic Oxides (Anhydrids). a. Ignite a small amount of sulfur in a deflagrating spoon by holding it in a Bunsen flame. Suspend the burning sulfur in a clean gas collecting bottle which contains about 25 cc. of water. When the sulfur no longer burns, remove it. Cover the bottle and shake to dissolve the gaseous product. Test the solution by dropping in blue litmus paper. Result. Explain. b. Repeat using carbon (charcoal). In this case it will be necessary to have the deflagrating spoon containing the carbon red hot before trying to burn it in the bottle, repeat- ing several times before there will be sufficient gas to give a noticeable action with water. Shake the gas into the water each time. Explain. Test with blue litmus paper letting it stand for some time. Put in a thin piece of apple peel. Result. Explain. c. Hold a short strip of magnesium in the forceps and ignite. Let the ash fall into a watch glass. Crush the ash to a powder. Add to this a few drops of water and slide the edge of the red litmus paper into this pasty mass. Allow this to remain until a decided change is apparent. Explain. d. Moisten a small lump of calcium oxid (lime) with water and test with red litmus paper. Result. Explain. LABORATORY MANUAL 203 Write the equations which show the union of the elements used with oxygen. Write the equations which show the union of water with the ox ids formed. Classify as metals or non-metals, these elements: sulfur, magnesium, carbon, calcium. Classify as acids or bases, the products obtained when the oxid of each is added to water. What is a basic oxid (basic anhydrid) ? What is an acid oxid (acid anhydrid) ? Chapter 9 Exercise 20. Salts. Neutralization. To an evaporating dish add 5 cc. of dilute sodium hydroxid and a drop of phenolphthalein indicator. Add dilute hydrochloric acid until the red color disappears and then add dilute sodium hydroxid very carefully until a faint pink color appears. The solution is now neutral with an excess of neither acid nor base. Evaporate off the water by boiling until it is nearly dry and crystals are present. What are these crystals? Taste them. Do they taste like either the base or acid with which you started? Write the equation. Why are acids used in treatment of burns by alkalies such as strong lye? Exercise 21. Hydrolysis. (a) Add one half spatula of sodium carbonate, sodium acetate, and ferric chlorid to separate test tubes and add water. Test the reaction of the solution with red and blue litmus. What causes these substances to react with litmus paper? Remember that only a very small part of the salt takes part in this reaction. (b) Repeat the experiment using sodium sulfate, sodium chlorid, and sodium nitrate. What do you conclude about the hydrolysis of these salts? Exercise 22. Hydrates. Water of Crystallization. Heat crystals of the following salts in a dry test tube: Potassium nitrate, sodium oxalate, 204 APPLIED CHEMISTRY FOR NURSES potassium oxalate, copper sulfate, magnesium sulfate, pure sodium chlorid. Note the appearance of appreciable quan- tities of water in the upper portion of the tube. (A small amount of water may be neglected.) Some salts contain water when they crystallize from solutions others do not. Did you destroy the chemical nature of the salt by driving off the water ? Efflorescence and deliquescence. Place a large crystal of each of the following salts on a labeled watch crystal and leave exposed to the air until the next laboratory period: sodium sulfate, calcium chlorid, sodium carbonate, calcium sulfate, magnesium chlorid, sodium nitrate. Note any changes that have taken place in the crystals. What are these changes? Plaster of Paris. Mix a little plaster of Paris on a block of wood with enough water to make a soft dough. Coat a coin or other small object with vaseline and press it into the plaster of Paris. After one half hour remove the coin and examine the cast. What is plaster of Paris? What is the reaction that causes it to harden? Exercise 23. Hard Water. Softening Temporary Hard Water. 1. Use of soap. Filter the "temporary" hard water if not perfectly clear. Pour 10 cc. of clear solution into a small flask, add a few drops of clear soap solution and shake thoroughly. Do suds form? Is there any evidence that a reaction has taken place? Continue adding the soap solution, a few drops at a time, shaking after each addition until suds form readily. Re- peat using 10 cc. of rain or distilled W'ater. Note the difference. 2. Boiling. Boil 10 cc. of clear hard water in a small beaker with cover glass, filter and add the soap solution as before. Do suds form more or less readily than in (1)? The "temporary" hard water has been softened by boiling. Try it with Sodium carbonate (washing soda). Ammonium hydroxid (ammonia water). Borax. Test with soap solution. Which is the most efficient ? LABORATORY MANUAL 205 Permanent Hard Water. Before testing rub some of the solution on the hands. Take 10 cc. and test with soap. Boil as before. Can this solution be softened by boiling? Try it with Sodium carbonate Ammonium hydroxid Borax. What will soften temporary hard water ? What will soften permanent hard water ? Chapter 10 Exercise 24. Tests for Metallic Elements. (a) Test for Sodium, Potassium and Lithium. Flame tests. Clean a platinum wire before each test by dipping it in hydrochloric acid and heating in the flame until no further colored flame appears. To a crystal of any available salt of each of these elements add a drop of hydrochloric acid. Dip the platinum wire in the acid solution of the salt and place in, the flame. Note the color of the flame and record. (b) Calcium. To 5 cc. of a solution of calcium chlorid add a few drops of dilute acetic acid and 1-2 cc. ammonium oxalate solution. A fine white precipitate is calcium oxalate. Test the faucet water for calcium in this manner. Test a sample of urine for calcium. (c) Magnesium. To 2-5 cc. of a solution containing magnesium add an equal volume of ammonium chlorid and 1-2 cc. of a solution of disodium hydrogen phosphate. A fine crystalline precipitate indicates magnesium. If the solu- tion contains calcium remove it by precipitating as in (b), filtering and testing the filtrate for magnesium. Test a sample of urine for magnesium after removing the calcium. (d) Iron. To 2-5 cc. of a solution to be tested for iron add an equal volume of dilute nitric acid and heat to boil- ing. Add 1-2 cc. of ammonium or potassium sulphocyanate. A red color indicates iron. (By heating with nitric acid the iron is converted to the ferric state which gives the red color; ferrous salts do not give this color.) 206 APPLIED CHEMISTRY FOR NURSES To a test tube add 1-2 drops of blood and 2-3 cc. of con- centrated nitric acid. Boil gently over the flame until the dark color disappears and the solution is light yellow. Cool under the faucet. Add about two volumes of water and 2-3 cc. of the sulphocyanate. Does the blood contain iron? (e) Mercury. Calomel. To tablets suspected of being calomel add dilute ammonium hydroxid. In case they turn black they are quite probably calomel. Bichlorid of mercury. These tablets are soluble in water. To the solution made acid with HC1 pass in hydrogen sul- fid. A black precipitate is formed. To the bichlorid solu- tion add 1-2 cc. of stannous chlorid solution. A silky precipitate is formed which will generally soon darken. In case both these tests are positive the substance contains mer- cury in the mercuric state. Chapter 11 Exercise 25. Tests for Non-Metallic Elements. (a) Chlorid. To 5 cc. of the solution to be examined add dilute nitric acid and silver nitrate solution. A pure white curdy precipitate indicates the chlorid ion. Test samples of urine and faucet water for this ion. (b) Sulfate. To 5 cc. of the solution to be examined, add dilute HC1 and a solution of barium chlorid. A fine white precipitate indicates the sulfate radical. Test urine and faucet water for this radical. (c) Carbonate. To the substance to be tested add dilute HC1. If a gas is liberated without heating it is probably CO2 from the carbonate radical. It may be further tested by passing it through lime water in which case a white pre- cipitate is formed. Test a sample of baking powder. (d) Phosphate. To 2-5 cc. of the solution to be tested add an equal volume of dilute nitric acid and 2-5 cc. of a solution of ammonium molybdate. Warm gently but do not boil. A fine yellow precipitate indicates the presence of the phosphate radical. Test a sample of urine. (e) Nitrate. To a few cc. of the solution to be tested add 1-2 cc. of ferrous sulfate and carefully underlay with LABORATORY MANUAL 207 concentrated sulfuric acid. A brown ring denotes the pres- ence of nitrate radical. (f) Ammonium. To a solution containing ammonium salts add an equal volume of dilute sodium hydroxide and boil. Recognize the escaping ammonia gas by i-ts odor or its action on red litmus paper. Bleaching. Place a little chlorinated lime in a test tube and add enough water to make a thin paste. Add a few drops of dilute sulfuric acid and then dip a piece of colored calico into the mixture. Remove the calico in a few minutes and wash in water. What is the change? What is the active agent in the bleaching powder which produces this change? Chapter 12 Exercise 26. Carbon and Carbon Dioxid. Distribution of Carbon, (a) Cover the bottom of a test tube with a thin layer of sand. Put on the sand a small piece of wood, a small wad of cotton and a lump of starch. Fill the test tube half full of dry sand and clamp it diagonally. Heat with a flame which extends just above the bottom of the test tube until the smoking ceases (approximately twenty minutes). After the tube has cooled sufficiently to handle it, pour the contents into a mortar. What is the residue? What is shown about the distribution of carbon? While the tube is heating, perform the following experi- ments : (b) Close the holes at the bottom of a lighted Bunsen burner and hold a glass tube in the upper part of the flame long enough for a thin deposit to form. What is it ? (c) Hold a glass tube in the flame of a candle and com- pare the result with that in (b). What do (b) and (c) suggest about the presence of carbon in combustible substances? Absorption by Charcoal. Fill a test tube one-third full of powdered animal charcoal. Add 10 cc. of brown sugar solution. Shake the tube thoroughly for a minute and then warm it gently. Filter through a wet filter paper into a 208 APPLIED CHEMISTRY FOR NURSES clean test tube. Compare the color of the nitrate with that of the original solution. Explain the change in color. Carbon Dioxid. Preparation. Fill a test tube about one* third full of broken marble, and add through the thistle tube just enough concentrated hydrochloric acid, diluted with an equal volume of water, to cover the marble. Collect three bottles of gas, cover them with glass plates, and put them aside until needed. Which side up ? Properties of Carbon Dioxid. (a) Plunge a burning stick several times into one of the bottles. What is the result? (b) Bend a splinter at right angles, light one end of it and lower it into a bottle of air. At once invert a bottle of carbon dioxid over it, holding the bottles mouth to mouth. What does the result of this experiment show about the density of carbon dioxid? (c) Pour a little limewater into a bottle of air and then add a bottle of carbon dioxid; cover the bottle with your hand and shake vigorously. Describe and explain the result. What is the test for carbon dioxid ? Carbon Dioxid and Combustion, (a) Exhale through a glass tube in a test tube half full of limewater. Describe and explain the result. (b) Lower a lighted candle into a bottle of air and allow it to burn for a few minutes. Remove the candle, pour a little limewater into the bottle and shake it vigor- ously. (c) Allow a stick of wood to burn for a short time in another bottle and then proceed as in (b). (d) Repeat (c) using a piece of paper in place of the wood. Is carbon dioxid formed in each of these experiments? Combustion of Illuminating Gas. Attach a medicine dropper to a rubber tube connected to the gas cock, light the gas at the point, and lower the small flame into a cold, dry bottle. Observe the result inside the bottle. Remove and extinguish the flame, add a little limewater to the bottle, and shake it. What are two products of the Fig. 5. LABORATORY MANUAL 209 combustion of coal gas? Of what two elements, therefore, are the constituents of illuminating gas composed ? Carbon Dioxid in Air. (a) Put about 5 grams of calcium hydroxid (slaked lime) in a bottle nearly filled with water, and, after shaking it thoroughly, filter a little of the lime- water thus prepared into a beaker. Expose the beaker of limewater to the air. What happens? To what is this action due? Chapter 13 Exercise 27. Alcohol. (a) Properties. Determine cautiously the odor and taste of ethyl alcohol. Drop a little on a glass plate. Is its rate of evaporation more rapid than that of water? Put a small piece of camphor in 10 cc. of alcohol and describe the result. Verify the solvent power of the alcohol by adding water to the solution of camphor. (b) Test. To one cc. of ethyl alcohol add about 5 cc. of a solution of iodin and potassium iodid. Add a solution of sodium hydroxid until the iodin color nearly disappears. Warm slightly. Note the yellowish precipitate of iodoform. Filter it on a small filter paper and allow it to dry. Note the odor. Iodoform is used as an antiseptic powder. (c) Preparation from Glucose. Mix about 30 cc. of Karo Syrup with 50 cc. of water in an Erlenmeyer flask. Add a quarter of a cake of yeast which has been rubbed up previously with 25 cc. of warm water. Place a one-hole rubber stopper in the flask and set it aside in your desk to ferment until the next exercise. At the next exercise open the flask and test for carbon dioxid and alcohol. How ? Carefully avoid shaking the flask. Decant off at least half the mixture into the other flask but do not allow the yeasty mass at the bottom to come over. Save it for a later experiment (acetic acid). Exercise 28. Aldehyds. Acetaldehyd. To one cc. alcohol add a few drops of cone. HC1 and 5 cc. potassium dichromate solution. Heat gently. Note the odor of the escaping gas. This is acetaldehyd. 210 APPLIED CHEMISTRY FOR NURSES Formaldehyd. Put a few cubic centimeters of methyl alco- hol in a test tube. Then wind a piece of copper wire around a glass rod or pencil. Slip the spiral from the rod, and, holding with the forceps, heat one end red hot in the flame. What is the color of the heated wire? Why? Then quickly drop it in the methyl alcohol. The pungent vapor is largely that of formaldehyd. What reactions have taken place ? What was the oxidizing agent in each case? Test for Formaldehyd. To 10 cc. milk in a porcelain casserol add 1 cc. of the solution to be tested for formaldehyd. Add 10 cc. of the acid-ferric chlorid reagent.* Heat slowly giving it a rotary motion to break up the curd. A violet color is produced when formaldehyd is present. This is a very delicate test. Milk occasionally contains formaldehyd as a preservative in which case of course it is tested directly. Exercise 29. Organic Acids. Acetic Acid, (a) Properties. Prepare a dilute solution of acetic acid and cautiously determine its taste, its odor and its reaction with litmus. Find what reaction sodium acetate gives with litmus. Is acetic acid a strong or a weak acid ? (b) Test for Acetic Acid and Acetates. Carefully add a few drops of cone, sulphuric acid to a mixture of equal volumes (3 or 4 cc.) of acetic acid and ethyl alcohol. The odor is due to the vapor of ethyl acetate. How can you use this reaction as a test for acetates and for alcohol? (c) Formation. Test with litmus the remainder of the solution resulting from the fermentation of the glucose. What acid is present? By what kind of a reaction was it formed? What was the catalyzer? Fatty Acids in Butter. Take a small quantity of butter in a test tube and heat over the flame with sodium hydroxid solution. Cool and make acid with hydrochloric acid. Warm and note the odor. This is mostly butyric acid. * Reagent is made by adding 0.2 co. of 10 per cent ferric chlorid to 100 cc. cone, hydrochloric acid. LABORATORY MANUAL 211 Chapters 14 and 15 Exercise 30. Carbohydrates. Test for Constituents. Put a little sugar in an evaporat- ing dish and heat. Invert a beaker over the top. Note the moisture collected. What is it? Remove the beaker and continue heating. Note the product. What is it? What are the constituents of carbohydrates? Tests for Reducing Sugars. Mix about 3 cc. each of the Fehling's Solution No. 1 and No. 2. Heat the mixture to make sure that it is good. Add a few drops of the sugar solution to be tested and boil for a minute or two. Test glucose, sucrose, lactose. Which are reducing sugars? Hydrolysis of Cane Sugar. To 3 cc. of cane sugar solu- tion add 3 drops of a weak solution of hydrochloric acid and boil for several minutes. Neutralize the acid with a drop or two of sodium hydroxid and test the solution with Fehling's as before. What change has taken place? Fermentation with Yeast. To solutions of sucrose, glu- cose, and lactose in a fermentation tube, add a small quantity of yeast cake. Incubate at 37° C. for a short period and note which ferment to produce a gas. What is the gas? What other product is formed? Starch, (a) Test. To a small portion of starch solution in a test tube, add a few drops of iodin solution. Result? Warm the solution. Result ? In testing for starch should one carry out the test in cold or hot solution ? WThy ? Test pieces of potato, rice, bread, and bean for starch by grinding them in a mortar with a little hot water before applying the test. (b) Add Hydrolysis. Use 25 cc. 1 per cent starch solu- tion. Test with Fehling's solution. Does it reduce? To the starch solution in a beaker add about 1 cc. of dilute sulfuric acid. Boil until a drop or two removed from the beaker gives no blue color with iodin solution. Neutralize the solution with dilute sodium hydroxid. Test with Fehling's. Does it reduce? Explain the action. (c) Digestion of Starch. To two-thirds of a test tube of starch solution add 1 or 2 cc. of saliva. In another test tube 212 APPLIED CHEMISTRY FOR NURSES place a similar quantity of starch solution. Place the test tubes in water in a beaker and by means of a low flame, keep the water at body temperature. At intervals remove a few drops of the solution from the first test tube and test with iodin solution. Note the color obtained each time. When the solution fails to give a blue color with the starch, test a sample of it with Fehling's solution. Result? Try Fehling's solution test on some starch solution which did not contain the saliva. What was present in the saliva? Exercise 31. Proteins. Prepare an albumin solution by thoroughly breaking up the white of an egg and adding about 100 cc. water. Note the flaky precipitate which is the globulin insoluble in water. Filter and use for the following protein reactions. Test for Nitrogen. Mix any solid or liquid protein with some solid soda-lime in a test tube and heat over the flame. After the water has been removed note the presence of am- monia gas by odor or wet litmus paper as it escapes from the tube. Color Reactions, (a) Xanthoproteic Test. Heat gently a little protein with a few drops of concentrated nitric acid. Note the color produced. Allow the tube to cool, then neu- tralize the acid with ammonium hydroxide. What change in color takes place? Test a solution of peptone. (b) Biuret Test. To protein add a solution of sodium hydroxid. To a test tube full of water add a drop or two of copper sulfate solution. Add a few drops of this diluted copper sulfate solution to the alkalin solution of the pro- tein. Note the color produced. Test a solution of peptone. Coagulation by Heat. To three separate test tubes add 5 cc. portions of the protein solution. To one add 2 drops of dilute acetic acid, to another add 2 drops of dilute sodium hydroxid. Place the three tubes in a beaker containing water and a thermometer. Heat the water in the beaker gradually while stirring. Note the temperature at which the three tubes of protein coagulate. What is the effect of alkali and acid on coagulation by heat? Precipitation by Metallic Salts. To small portions of the protein solution in test tubes add solutions of the following LABORATORY MANUAL 213 salts: Silver nitrate, mercuric chloric!, barium chlorid, so- dium chlorid, ferric chlorid. Which salts precipitate protein ? Digestion of Proteins. In each of the three tubes place a small amount of grated white of hard boiled egg. To the first add 5 cc. of artificial gastric juice (dilute hydrochlorid acid and pepsin). To the second add 5 cc. of artificial pan- creatic juice (pancreatin and sodium carbonate) ; to the third add 5 cc. of water and use as the control. Place the test tubes in a beaker of water and keep it about body tem- perature for a few hours, filter the contents of each tube. Is there any evidence of digestion? Try the Biuret test on the filtrate. Exercise 32. Fats. Test. To a little fat in a test tube add a few crystals of solid potassium bisulfate. Heat over the flame and note a sharp penetrating odor coming from the tube. This is acrolein and is formed from dehydration of the glycerin in the fat molecule. Preparation of a Soap. Melt about 5 gm. of fat in an evaporating dish, stirring constantly while heating. When melted, add gradually 25 cc. of 10 per cent sodium hydroxid, heating it into the fat to prevent burning. What reaction takes place ? Add 50 cc. of a strong solution of common salt, mix and allow to cool. When cold, lift out the cake of soap, wash well with cold water, melt it with 20 cc. of water, mix- ing well and cool again. What is soap ? Emulsification of Fats. To 10 cc. of water, in a test tube, add about 1 cc. of cotton seed oil or olive oil. Shake vigor- ously and let stand a few minutes. Result? Now add 3 cc. of a soap solution. Shake again and observe as above. What is the effect of soap solution? Digestion of Fat. To 20 cc. of milk add a little litmus solution. If the reaction of the milk is found to be acid, make it slightly alkaline by adding dilute solution of sodium carbonate. Divide equally into two test tubes. To one of these test tubes add a little artificial pancreatic juice. If the color of the liquids in the two test tubes is not exactly the same after this addition to one of them, make it so by adding sodium carbonate solution to the one that needs it. 214 APPLIED CHEMISTRY FOR NURSES Put both tubes into a beaker of water and keep at body temperature for an hour. Result ? What has been produced ? What does it indicate? Butter and Substitutes. Melt a piece of oleomargarine about the size of a chestnut in a dish over a small flame, stirring constantly until the fat melts and boils. Note the amount of sputtering and frothing. Repeat with butter. How can you distinguish fresh butter from substitutes? Chapter 17 Exercise 33. Chemical Analysis of Blood. To a small Erlenmeyer flask add 5 cc. fresh blood, 20 cc. distilled water, 2 cc. of dilute (10 per cent) sulfuric acid. Mix. Finally add 5 cc. of 10 percent sodium tungstate and shake very thoroughly. Filter. The filtrate should be per- fectly water clear. The sulfuric acid and sodium tungstate forms tungstic acid. What has the tungstic acid removed? Test the filtrate as follows: To 2-3 cc. of Folin-Wu Sugar Reagent (a modified Fehling's solution) in a test tube add an equal volume of the filtrate. Heat in boiling water for 5-8 minutes. A yel- lowish red precipitate indicates sugar. Note: The blood must be fairly fresh to give a good sugar test. To a few cc. of the filtrate add a few drops of nitric acid and 1-2 cc. of silver nitrate. What does the precipitate indicate ? This filtrate also contains urea, uric acid, creatinin amino acids, etc. By proper manipulation quantitative analyses are performed. Chapter 18 Exercise 34. Analysis of Bone. (a) Weigh on a balance, as accurately as convenient, about 5 gm. of fresh bone from which the meat has been well re- moved. Place in a porcelain crucible and heat over the flame until all the organic matter has burned away. Cool and weigh LABORATORY MANUAL 215 again. From these data calculate what percentage of the bone is mineral matter. (b) Take the ash from the above experiment or 2-3 gm. of bone ash and make the following analyses: To the ash in a beaker add about 20 cc. of dilute nitric acid. What does the effervescense indicate? What radical is present in the ash? Add an equal volume of water and filter. Save the filtrate and discard the residue. To this acid filtrate add ammonium hydroxid until the re- action is alkalin. A white precipitate forms. Filter this and save both filtrate and precipitate. Test the filtrate for sulfate and chlorid according to direc- tions in Exercise 25. Remove a small portion of the precipitate to a test tube and dissolve in dilute acetic acid. Add ammonium oxalate. A precipitate indicates what? Remove another small portion to a test tube and dissolve in dilute nitric acid. Test for PO4 radical as in Exercise 25. Exercise 35. Analysis of Milk. To about 20 cc. skim milk in a beaker add an equal volume of water and heat to boiling. As it boils add a few drops of dilute acetic acid until a nice floculant precipitate forms. Filter. Test the precipitate with the biuret and the xantho- proteic reaction. Concentrate the filtrate by boiling to about 10 cc. Test this concentrated filtrate for Ca. PO4, and Cl by methods mentioned before. Also test a portion with Fehling's solution. Is a reducing sugar present? If so which one? Chapter 19 Exercise 36. Analysis of the Urine. Normal. Procure a sample of your own urine for these analyses. Note the color and the presence of any sediment. (A sediment is often normally present in a specimen of urine excreted after a meal. It consists of phosphates and is soluble in dilute acetic acid.) Determine the specific gravity with a urinometer. 216 APPLIED CHEMISTRY FOR NURSES Dip a piece of red and a piece of blue litmus in the urine and place on a white paper. Is the reaction acid or alkalin ? Test the urine for the following ions by methods given previously in the manual: Ca, Mg, Fe, NH4, SO4. P04, Cl, CO3. Pathological. Samples are provided for you which con- tain these pathological constituents. (a) Albumen. Fill a test tube % full of the urine sus- pected of containing albumen. Add 2-3 drops of dilute acetic acid. Holding the bottom of the test tube in the hand heat the upper part of the urine nearly to boiling. Examine in the light. Any precipitate in the upper portion indicates albumen. Results are reported as faint trace, trace, cloud, mass and boiled solid, according to the amount present. (The acetic acid will dissolve any phosphates which may be pre- cipitated by the heat.) (b) Sugar. Heat Fehling's or Benedict's solution to boil- ing and add a few drops of the urine to be tested. A red or yellow precipitate indicates the presence of sugar. (Chloro- form should not be used with urines to be tested for sugar.) (c) Acetone Bodies. To about 5 cc. urine add a small crystal of sodium nitroprussid and shake to dissolve a por- tion of the crystal. Make alkaline with potassium hydroxid. A red color is produced. Make acid with acetic acid. If acetone is present the color remains or is intensified while if it is absent a light yellow solution is formed. (d) Bile. Carefully underlay a few cc. urine to be tested with cone, nitric acid. At the zone of contact various colored rings are formed if the reaction is positive. If the reaction is positive note at the zone of contact the various colored rings: red, green, violet. (This is a test for bile pigments.) To 5 cc. urine add 5 drops of 5 per cent cane sugar. Care- fully hold the test tube in the running water from the faucet to keep it cool and run 2-3 cc. of concentrated sul- furic acid under the urine. Shake the tube slightly keeping it cool under the water. Note the red ring at the zone of contact in case the test is positive. (This is a test for bile acids.) (e) Blood. To a saturated solution of benzidin in glacial acetic acid add an equal volume of 3 per cent hydrogen peroxid LABORATORY MANUAL 217 and a small amount of the urine under examination. The presence of blood is shown by an intense blue color. (f) Indican. Nearly fill a test tube with equal volumes of urine and Obermayer's reagent.* Add 2-3 cc. chloroform and shake by placing the thumb over the mouth of the tube. Note the color of the chloroform. (g) Make microscopic examination of the urine if possible. Note: It is realized that in these experiments many of the details are omitted and need to be supplied by the instructor. This is purposely done so that the instructor may choose experiments most closely associated with the material being presented in the classroom and that she may supply details of experiments as the exigencies of the laboratory may demand. * Obermayer's reagent: Dissolve about 1 gm. ferric chlorid in 500 cc. cone, hydrochloric acid. PREPARATION OF SOLUTIONS AND REAGENTS The following solutions should be made with distilled water. Always dissolve the substance and finally dilute to required volume. For instance in making 10 per cent mag- nesium sulfate solution do not add 10 gm. magnesium sul- fate to 100 cc. water, but dissolve 10 gm. magnesium sulfate in 80-90 cc. water and after solution dilute to 100 cc. Unless special accuracy is required and so mentioned an ordinary trip scale weighs the chemicals with sufficient accuracy. Dilute sulfuric acid, 10 per cent: Dilute 60 cc. cone, sul- furic acid to one liter with water. Dilute nitric acid, 10 per cent: Dilute 100 cc. cone, nitric acid to one liter with water. Dilute hydrochloric acid, 10 per cent: Dilute 250 cc. cone, hydrochloric acid to one liter with water. Dilute acetic acid, 10 per cent; Dilute 100 cc. cone, acetic acid to one liter with water. Dilute ammonium hydroxid, 10 per cent: Dilute 400 cc. cone, ammonium hydroxid to one liter with water. Dilute sodium hydroxid, 10 per cent: Weight out 105 gm. of stick sodium hydroxid, dissolve in water with stirring and cool. Dilute to one liter. Phenolphthalein indicator: Dissolve 1 gm. phenolphthalein in 100 cc. alcohol (95 per cent). Methyl orange indicator: Dissolve 0.1 gm. methyl orange in 100 cc. water. "Normal" saline: Dissolve 9 gm. of pure sodium chlorid in water and dilute to one liter. Lime water (saturated Ca(OH)2) : To a liter of water add about 5 gm. of calcium oxid, shake well, allow to stand a number of hours. Remove the clear liquid for use. 218 PREPARATION OF SOLUTIONS 219 Fehling's solution: A. Dissolve 35 gm. copper sulfate in water and dilute to 500 cc. B. Dissolve 125 gm. potassium hydroxid and 173 gm. Rochelle salt (sodium potassium tartrate) in water and dilute to 500 cc. Preserve the solutions separately and mix equal volumes as needed for tests. Folin-Wu blood sugar reagent: In about 200 cc. water dissolve in succession 20 gm. pure anhydrous sodium car- bonate 3.75 gm. tartaric acid, 2.25 gm. copper sulfate. Mix and dilute to 500 cc. lodin solution: Dissolve 20 gm. potassium iodid in water, add 10 gm. iodin, dissolve and dilute to one liter. Benzidin: Saturated solution in cone, (glacial) acetic acid. Ammonium molybdate: Dissolve 10 gm. of ammonium molybdate in about 90 cc. water. Add 5 cc. cone, nitric acid and dilute to 100 cc. Prepare the following chemicals in 10 per cent solution: Tartaric acid, potassium hydroxid, stannous chlorid, am- monium chlorid. Prepare the following chemicals in 5 per cent solution: sodium chlorid, calcium chlorid, magnesium sulfate, silver nitrate, ferric chlorid, barium chlorid, ammonium oxalate, oxalic acid, di sodium hydrogen phosphate, potassium per- manganate, potassium dichromate, potassium or ammonium sulphocyanate, cane sugar. 220 APPLIED CHEMISTRY FOR NURSES Approximate Equivalents Metric .001 gram ( 1 milligram) .... 1/64 grain .015 gram (15 milligrams) .... 1/4 grain .065 gram (65 milligrams) .... 1 grain 1 gram 15 grains 1 c.c 15 minims 4 grams 1 dram 4 c.c , 1 fluid dram 30 c.c 1 fluid ounce 30 grams 1 ounce 500 c.c 1 pint 1,000 c.c 1 quart 1 liter . .. . 1 quart 1 kilogram 2.2 lbs. (avoirdupois) 1 meter 39.37 inches (c.c. = cubic centimeter) Meter-Length Kilometer 1,000 Meters Hectometer 100 Meters Dekameter 10 Meters 0.1 m 1 Decimeter 0.01 m 1 Centimeter 0.001 m 1 Millimeter Liter-Capacity Kiloliter 1,000 Liters Hectoliter 100 Liters Dekaliter 10 Liters 0.1 L 1 Deciliter 0.01 L 1 Centiliter 0.001 L 1 Milliliter (mil) (c.c.) Gram-Weight Kilogram 1,000 Grams Hectogram 100 Grams Dekagram. 10 Grams 0.1 gm 1 Decigram 0.01 gm 1 Centigram 0.001 gm 1 Milligram TABLES 221 Centigrade • Fahrenheit Boiling Point 100 212 95 203 90 194 85 185 80 176 75 167 70 158 65 149 60 140 55 131 50___________122 45 113 40 104 Body Temperature 37 98.6 35 95 30 86 25 77 Room Temperature 20 68 15 59 10 50 5 41 Freezing Point 0 32 For every five degrees on the Centigrade scale there are nine degrees on the Fahrenheit scale , 0 Rule: To convert Fahrenheit to Centigrade Subtract 32 and Multiply by 5/9. To convert Centigrade to Fahrenheit Multiply by 9/5 and add 32. 222 APPLIED CHEMISTRY FOR NURSES Ink. Ordinary fountain pen ink is a solution of fer- rous tannate. This solution is colorless and in order to make the writing visible a blue dye is added. On ex- posure to the air, the ferrous tannate is oxidized to ferric tannate, a black, insoluble salt. Since ferrous tannate, as well as the dye, is soluble in water, fresh ink stains may be removed from a fabric by washing it in water. To remove old stains it is necessary to reduce the ferric salt to ferrous tannate. A weak solution of oxalic acid or the citric acid of lemon juice will act as a reducing agent. Important Elements with their Valences and Approximate Atomic Weights Atomic Valence Weight Potassium I. 39 Sodium . . I. 23 Calcium . . . II. 40 Aluminum .. III. 27 Zinc II. 65 Iron .. III., II 56 Nickel ... . II. 58.7 Tin .. IV., II 119 Lead II. 207 Hydrogen . I. 1 Copper ... .. L,II 63.6 Atomic Val ence Weight Antimonv . . III. 120 Bismuth . .. . III. 208 Mercury . .. I., II 200 Silver I. 108 Bromine ... I. 80 Chlorine .. . I. 35.5 Iodine I 197 Sulphur . . IL, IV., VI 32 Phosphorus . III., V 31 Oxygen .... . II. 16 Nitrogen . . III., V 14 Arsenic . .. . III., V 75 Radicals and their Valences Valence Hydroxide (OH) .. I. Ammonium NH4 . . I. Nitrate NO, I. Nitrite NO2 I. Chlorate C1O3 .... I. Valence Carbonate CO3 ... ... II. Sulphate SO4 .... ... II. Sulphite SO3 . .. . ... II. Phosphate PO4 .. . ... III. Phosphite PO3 . .. ... III. INDEX Absorption, 149 of Amino acids, 149 of Fats, 149 of Glucose, 149 of Inorganic salts, 149 of Water, 149 Acetates, Test for, 210 Acetic Acid, 114 Acetone, 113 in urine, 175 Acetylene, 110 Acid, 114 action with: bases, 62 carbonates, 63 cells, 64 indicators, 62 metals, 62 salts, 64 amino, 122 butyric, 116 citric, 115 composition of, 61 experiments, 201 fatty, 116 formulas of common, 60 hydrochloric, 64 in gastric juice, 64 ionization of, 61 lactic, 115 malic, 115 nitric, 94 oleic, 117 organic, 114 oxalic, 115 palmitic, 116 phosphoric, 61 radical, 61 salicylic, 120 salts, 76 stearic, 116 Acid-Continued strong, 64 sulfuric, 99 tartaric, 115 weak, 64 Acidosis, 160 Acid Oxids, 70 experiments, 202 Activity, order of metals, 38 Adrenalin chlorid, 32 reduction of, 32 sterilization of, 32 Air, 25 carbon dioxid in, 103 composition, 25 effect on metals, 83 nitrogen in, 93 oxygen in, 25 Alcohol, 111 characteristic formula group, 111 ethyl, 112 denatured, 111 glycerine, 112 methyl, 111 test for, 209 Alcoholic fermentation, experi- ment, 209 Aldehyds, 112 characteristic formula group, 112 acetyl aldehyd, 113 experiments, 209 formaldehyd, 113 Alkalies, 68 burns, 70 effect on wool, 69 in soap, 69 strong, 68 Alkaline reaction, 68 Alkaloids, 123 223 224 INDEX Allotropic forms, 35 Alloys, 83 Aluminum, 89 Amids, 123 Amins, 123 Amino acids, 122 absorption of, 149 metabolism of, 150 Ammonia, 93 for refrigeration, 94 Ammonium carbonate, 150 hydroxid, 69 Amorphous carbon, 102 Amylases, 141 Amylopsin, 144 Animal charcoal, 102 Anhydrates, 7 8 Arsenic, 99 Atoms, 10 Atomic weights, 13 Avogadro's hypothesis, 48 Bacteria, denitrifying, 95 in intestines, 146 in water, 51 nitrifying, 95 Baking powder, 104 Barium sulfate, 85 Barley water, 55 Basal metabolism, 152 Bases, 67 action with: acids, 67 indicators, 67 composition of, 68 experiments, 201 formulas of common, 68 ionization of, 68 strong, 68 Base oxids, 70 experiment, 202 Benzene ring, 118 Benzoic acid, 119 Bile, 167 action on fats, 144 in urine, 216 pigment, 167 salt, 167 Bismuth subnitrate, 76 Bleaching, 31 Bleaching powder, 96 Blood: calcium salts in, 156 carbon dioxid in, 157 chemical examination of, in disease, 157 clotting of, 156 composition of, 155 corpuscles, 155 experiments on, 214 function, 155 gases in, 157 plasma, 155 serum, 156 sodium salts in, 156 withdrawing for tests, 161 Body excretions, 173 Boiling point, 4 of electrolytes in solution, 59 of non-electrolytes in solution, 60 of water, 50 Bonds, 109 Bone, 165 experiment on, 214 Borax, 100 Boric acid, 100 Boron, 100 Boyle's Law, 45 Brass, 83 Bromids, 97 Bromin, 97 Burning, 29 Butane, 110 Butter, to distinguish from sub- stitutes (experiment), 214 Butyric acid, 116 Calcium, 84 acid carbonate, 80 carbonate, 85 chlorid, 79 hydroxid, 70 in blood, 156 oxid, 70 salts in hard water, 136 sulfate, 78 Calomel, 89 Calorie, 152 large, 152 INDEX 225 Calorie-Continued small, 22 Calorimeter, 22 bomb, 151 Cane Sugar, 128 Carbohydrates: absorption of, 149 classes of, 128 composition, 127 digestion in: intestines, 144 mouth, 142 energy from, 152 experiments on, 211 fermentation of, 129 fermentation in intestines, 147 how plants obtain, 130 in blood, 151 oxidation of, 151 storage of, 151 Carbolic acid, 119 Carbon, 102 amorphous, 102 crystalline, 102 experiments, 207 Carbon dioxid, 103 action on lime water, 103 carbonated waters, 105 effect on respiration, 103 excretion of, 103 experiments, 207 in fire extinguishers, 105 production in air, 103 in blood, 103 in cooking, 104 use by plants, 103 Carbonates, 105 effect of acids on, 63 experiments, 201 in intestine, 143 Carbon monoxid, 106 poisoning, 106 treatment for, 106 Carbon tetrachlorid, 120 Casein, 143 Catalytic agent, 27 effect of, 27 experiment, 196 Cellulose, 129 Charcoal, 102 decolorization by, 102 (experiment), 207 Charles' Law, 46 Chemical change, 6 experiments showing types of, 195 types of, 18 Chemical energy, 21 Chemistry: branches of, 3 definition, 1 history, 1 importance to nurses, 2 Chlorin, 96 bleaching by, 96 Chlorinated lime, 96 Chloroform, 120 Chyme, 143 Citric Acid, 115 Coagulating' protein, 131 Coal, 102 Coal Tar Products, 120 Cod Liver Oil, 138 Coke, 102 Colloids, 54 Combustion, 29 essentials for, 29 spontaneous, 30 Compounds, 10 constituents of, 10 distinguishing from mixtures, 12 experiments, 194 formation of, 10 stable, 11 Component, 12 Condensation, 4 Conductivity of electrolytes, 59 Conductor, 58 Constituent, 10 Copper, 88 cleaning, 88 compounds, 88 for cooking utensils, 88 in moist air, 88 Corn syrup, 127 Corrosive sublimate, 88 Crystallization, water of, 78 experiment, 203 226 INDEX Cuprous oxid, 88 Cyanogen, 96 Dakin's solution, 97 Dalton's Atomic Theory, 16 Decomposition, 19 double, 19 Deficiency diseases, 138 Definite proportions, law of, 14 Deliquescence, 79 experiments, 204 Denatured alcohol, 111 Denitrification by bacteria, 95 Desiccated drugs, 78 Dextrose, 127 in blood, 128 Diabetes, 159 blood chemistry in, 159 Diet, complete, 139 Digestion, 141 in intestines, 143 in mouth, 142 in stomach, 142 of carbohydrate, 142 of fat, 142 of protein, 142 Direct combination, 18 experiment, 195 Disaccharids, 128 Disinfection: by chlorin, 96 by drying, 49 by hydrogen peroxid, 41 by permanganate potassium, 31 by sulphurous acid, 71 Displacement, 19 experiment, 195 Dissociation, 59 Distillation, 4 destructive, 120 Distilled water, 52 effect on blood cells, 56 Double decomposition, 19 experiment, 195 Effervesence, 41 Effervescing powders, 63 Efflorescence, 79 experiment, 204 Egg white, 131 Electricity, 58 Electrolysis, 59 Electrolytes, 59 Elements, definition, 8 active, 11 common, 8 in human body, 8 inert, 11 names, 9 origin of names, 9 Emulsification by bile, 144 Emulsion, 136 Endocrine glands, 170 Energy, 19 chemical, 21 forms of, 20 from carbohydrates, 152 from fats, 152 from proteins, 152 indestructibility of, 21 transformation of, 20 Enterokinase, 144 Enzymes, 141 amylases, 141 in gastric juice, 142 in intestinal juice, 144 in pancreatic juice, 144 in saliva, 142 lactase, 144 lipases, 144 maltase, 144 proteoses, 142 sucrase, 144 Equation: chemical, 14 its significance, 14 thermochemical, 22 Erepsin, 145 Esters, 117 Ethane, 110 Ethers, 117 Ether, 118 anesthetic, 118 as solvent, 118 Ethyl: acetate, 117 alcohol 112 preparation, experiment, 20n properties, experiment, 209 test for, 209 chlorid, 122 names, 9 INDEX 227 Ethylene, 110 Evaporation, 12 Excretions of body, 173 Exsiccated drugs, 78 Extractives, 166 Fats: absorption of, 149 digestion in intestines, 143 digestion in stomach, 142 emulsion of, 136 experiments on, 213 in the body, 134 properties, 136 saponification of, 135 solubility of, 136 use in making soap, 135 Fatty Acids, 116 Feces. 146 Fehling's solution, 219 Fermentation: in intestines, 147 of carbohydrate, 129 experiment, 211 Filtrate, 12 Fire, extinguishing of, 30 Fixation of nitrogen, 95 Fluorin, 96 Foods, composition of, 126 Formaldehyd, 113 experiment, 210 test for, 210 Formic acid, 116 Formula, 11 significance of, 11 structural, 109 Fowler's solution, 99 Freezing point, 4 of electrolytes in solution, 60 of non-volatile electrolytes, 60 of water, 50 Gases, diffusion of, 44 experiment, 198 Gas laws, 45, 46 Gastric juice, 142 analysis of, 143 Glands of internal secretion, 170 Glass, 99 Glucose, 127 in blood, 128 test for, 129 Glycerine, 112 Glycogen, 129 Gold, 91 Grain alcohol, 112 Grape sugar, 127 Gypsum, 78 Halogens, 96 derivatives, 120 Hard soap, 135 Hard water, 80 Heat, measurement of, 22 loss from body, 34 of solution, 54 Hemoglobin, 33 Hemolysis, 56 Hormones, 144 Hydrates, 77 experiments, 203 Hydrocarbons, 109 Hydrochloric acid, 64 in gastric juice, 64 Hydrogen, physical properties, 37 chemical behavior, 37 experiments, 197 preparation of, 39 Hydrogen peroxid, 40 action in wounds, 41 bleaching by, 41 experiments, 197 uses of, 41 Hydrogenation, 40 Hydrolysis of salts, 76 experiments, 203 Hydrolysis of: fat, 143 experiment, 213 protein, 142 experiment, 213 starches, 145 experiment, 211 sugars, 145 experiment, 211 Hydroxids, 67 ammonium, 69 calcium, 70 sodium, 68 228 INDEX Hydroxids-Continued potassium, 68 Hypertonic solutions, 162 Hypoacidity, 64 Hypothesis, Avogadro's, 48 Hypotonic solutions, 162 Indican in urine, 175 Indol, 146 Insulin, 159 Intestines, 143 absorption from, 145 digestion in, 143 fermentation in, 146 putrefaction, 146 lodids, 97 lodin, 97 tincture of, 97 Iodoform, 120 Ionization theory, 59 Iron, 86 compounds, 87 in blood, 87 Isomers, 108 Isotonic solutions, 162 Jaundice, 167 Juice: gastric, 142 intestinal, 144 pancreatic, 144 Ketones, 113 Kidney functional tests, 176 Kidney stones, 177 Kindling temperature, 29 Kinetic Molecular Hypothesis, 43 Laboratory experiments, 193 acids, 201 alcohol, 209 aldehyds, 209 bases, 201 blood, 214 bone, 214 carbon, 207 carbon dioxid, 207 carbohydrates, 211 compounds, 193 diffusion of gases, 198 diffusion in a liquid, 198 Laboratory experiments-Cont. dissolved salts and boiling point, 200 fats, 213 hard water, 204 hydrates, 203 hydrogen, 197 hydrolysis, 203 metallic elements, test for, 205 milk, 215 non-metallic elements, test for, 206 organic acids, 210 osmotic pressure, 200 oxidation and reduction, 197 oxygen, 195 physical and • chemical change, 193 proteins, 212 salts, 203 solubility, 199 types of chemical change, 195 urine, 215 water, 198 Lactic acid, 115 Lactose, 128 Law, Boyle's, 45 Charles', 46 of conservation of matter, 15 of definite proportions, 14 Lead, 90 Levulose, 128 Limestone, 85 Lime water, 70 Lipases, 144 Litmus, 62 action with acids, 62 action with bases, 67 Liver, 166 Living matter, 126 characteristics of, 126 Lunar caustic, 95 Lungs, surface area of, 33 Lye, 68 Lymph, 157 Magnesium, 84 hydroxid, 68 oxid, 70 sulfate, 85 INDEX 229 Malic acid, 115 Maltose, 128 Mammary gland, 168 Manganese dioxid, 26 as a catalyst, 26 experiment, 196 Marble, 85 Matter, 3 kinds of, 3 melting point, 4 Mercuric chlorid, 88 precipitation of protein by, 133 treatment for poisoning by, 88 Mercurous chlorid, 88 Mercury, 88 Metabolism, 149 of amino acids, 149 of fats, 151 of glucose, 151 Metallic elements: tests for, 205 Metals, effect of air on, 83 heating in air, experiments, 193 order of activity of, 38 with salts, 84 with water, 39 Methane, 109 Methyl alcohol, 111 Methyl orange, 62 action with acids, 62 with bases, 67 Methyl salicvlate, 120 Milk, 168 analysis of, experiment, 215 composition of, 169 Mixtures, characteristics, 11 distinguished from compounds, 12 experiment, 194 Molecule, 10 Molecular weight, 13 Monosaccharids, 128 Muscles, protein in, 166 rigor mortis in, 166 Nephritis, blood chemistry in, 158 Nervous tissue, 166 lipoids in, 166 protein in, 166 Neutralization, 73 experiment, 203 Nickel, 87 rusting of, 28 Nitrates, 94 Nitric acid, 94 Nitrification by bacteria, 95 Nitrites, 94 Nitrogen, 93 fixation of, 95 importance to man, 93 in air, 93 in protein, 93 test for, 212 Nomenclature, 75 of acids, 75 of salts, 75 Non-metallic elements, 93 test for, 206 Normal saline, 162 Olive oil, 135 Organic acids, 114 characteristic formula group, 114 experiments, 210 Organic chemistry, 108 Osmosis, 55 Osmotic pressure, 55 experiment, 200 Oxalic acid, 115 Oxidases, 33 Oxidation, 28 Ox ids, 28 acid, 70 basic, 70 Oxidizing agents, 30 Oxygen, 25 administration of, 34 chemical properties, 27 effect on bacteria, 31 effect on metals, 28 experiments, 195 in the body, 32 occurrence, 25 physical properties, 27 preparation, 25 Oxyhemoglobin, 33 Ozone, 34 Palmatin, 135 230 INDEX Palmitic acid, 116 Pancreatic juice, 144 Pepsin, 142 Peptones, 142 Petroleum, 109 Phenol, 119 Phenolphthalein, 62 action with: acids, 62 bases, 67 Phenolsulphonephthalein test, 176 Phosphorus, 98 Phosphates, 99 Physical change, 5 nature of, 5 types of, 5 Plasma, 155 Plaster of Paris, 78 Platinum, 91 Polysaccharids, 128 Potassium, 84 chlorate, 26 hydroxid, 68 permanganate, 31 Precipitate, 6 Propane, 110 Proteins, 130 color reactions, 212 conjugated, 131 derivatives, 132 digestion of, 142 non-diffusibility of, 133 precipitation of, 133 experiments, 212 simple, 131 Proteoses, 142 Ptyalin, 141 Putrefaction in intestines, 146 Radicals, 17 Radioactivity, 85 Radium, 85 Reducing agents, 31 Reducing sugar, 129 test for, 211 Rennin, 143 Residue, 12 Review Questions, 179 Rochelle salt, 104 Rust, 28 Salicylic acid, 120 Saline normal, 162 Saliva, 142 Salting out, 134 Salts, 73 acid, 76 basic, 76 composition, 73 double, 76 hydrolysis of, 76 importance in diet, 137 in hard water, 80 methods of obtaining, 74 nomenclature of, 75 Saponification, 135 Saturated solution, 53 Scale in kettles, 80 Scurvy, 138 Secretin, 144 Secretions: internal, 170 intestinal glands, 144 pancreatic, 144 stomach glands, 142 Semi-permeable membrane, 55 Serum, 156 Silicon, 99 Silver, action with sulfur, 89 cleaning of, 89 nitrate, 94 Silver nitrate, 95 Soap, 135 action with hard water, 135 formation in intestines, 145 preparation of, 135 experiment, 213 test for free alkali in, 202 Soap powder, 69 Sodium, 84 action with water, 39 bicarbonate, 77 carbonate, 77 chlorid, 97 hydroxid, 68 Sodium bicarbonate solution, 77 hydrolysis of, 77 sterilization of, 77 INDEX 231 Sodium carbonate, 77 Softening of water, 80 experiments, 204 Solubility, experiments, 199 factors effecting, 52 Solute, 52 Solutions, 52 boiling points of, 54 colloidal, 54 experiments, 199 Fehling's, 219 Fowler's, 99 freezing points of, 54 heat of, 54 saturated, 53 supersaturated, 53 unsaturated, 53 Solvent, 52 Stannic compounds, 90 Stannous compounds, 90 Starch, digestion of, 142 experiments, 211 formation in plants, 130 States of matter, 3 Steapsin, 144 Stearic acid, 116 Stools, examination of, 147 Strong Acid, 64 bases, 68 Strontium, 84 Structural formula, 109 Sublimation, 4 Substances, 3 identification of, 4 Sucrase, 144 Sucrose, 128 Sugar beet, 128 Sugar in milk, 128 Sugar tolerance test, 159 Sulfuric acid, 99 Sulfurous acid, 71 Sulfur, 99 action with silver, 89 dioxid, 70 fumigation with, 70 Supersaturated solution, 53 Supporting tissues, 165 Symbols, 9 for common elements, 9 Tar, coal, 120, 121 wood, 121 Tartaric acid, 115 Thermochemical equation, 22 Tin, 90 Tincture of iodin, 97 Transformation of energy, 20 Urea, 123 Urine, examination of, 175 albumen in, 175 analysis, 215 bile in, 216 blood in, 176 indican in, 175 specific gravity, 175 sugar in, 175 reaction of, 174 Valence, 16 Vaporization, 4 Vitamines, 137 Washing soda, 77 Water, 49 absorption of, 146 action of metals above hydro- gen on, 39 as a solvent, 52 composition, 49 distilled, 52 experiments, 198 foreign matter, 51 hard, 80 infected, 51 importance of, 49 mineral substances in, 51 occurrence of, 49 physical properties, 50 polluted, 51 supply of, 49 Weak acid, 64 Weight, atomic, 13 molecular, 13 W7ood alcohol, 111 Wood, distillation of, 120 Wood tar products, 121 Zinc, 90 oxid, 90