Complete Text (Part 5)

a rule, differ widely from those of their component molecules. 119. All changes in the composition and structure of molecules are chemical changes and are governed by chemical energy in accordance with chemical laws of nature. The formation, relative stability, transformation and decomposition of molecules all depend upon chemism, but chemism is decidedly affected by other forms of energy, such as heat, light, electricity, and even cohesion and adhesion. 120. Any and every chemical change is chemical action and reaction. Among the most familiar examples of chemical action are fire, explosions, fermentation, decay, the action of metals and many other substances upon acids, and the corrosive action of strong lye upon animal and vegetable matter. Fire, or combustion, is chemical action accompanied by the evolution of large quantities of heat and light. This is the chief source of heat available for the use of man. When carbon and oxygen unite, heat and light are both produced, but in many chemical reactions no light is evolved, though heat may be liberated in large quantities. If water be poured upon unslaked lime, chemical action results, and the mixture grows very hot, but no light is seen. The same phenomenon may be noticed when dilute sulphuric acid and ammonia water are mixed. Heat indirectly aids chemical action. Some reactions are begun only in the 42 A CORRESPONDENCE COURSE IN PHARMACY presence of heat, but after once started the heat generated by the reaction is sufficient to keep up the process. It is necessary to heat wood or coal to a certain point to compel ignition, but once burning, the fire continues as long as coal or wood and oxygen are supplied. Test Questions To the Student: Again consult your Student's Guide, so that you will make no mistake as to the form and arrangement of your paper. Before writing this paper, review carefully the paper on Lesson II. That will undoubtedly contain some criticisms and suggestions which will assist you in writing your paper on this lesson. You should aim to make each paper freer from error and in every way stronger than the previous one. Do not consult the text-book while writing. Be careful with your penmanship. It is especially important that a pharmacist write a neat, legible hand. Your spelling, too, should be accurate. A pharmacist easily might be led into serious mistakes by errors in spelling. The new words Of these lessons should be made a part of your vocabulary at once. Where terms are similar be sure to distinguish between them. Accuracy in everything, is the pharmacist's motto. 1. Define cohesion. 2. What are the effects of adhesion ? 3. How may cohesion be overcome ? 4. Under what conditions do cohesion and adhesion oppose each other ? 5. What is meant by a fluid ? 6. What is the difference between gas and vapor ? 7. What is the meaning of the word temperature and what causes the difference between a high temperature and a low temperature ? 8. Mention several means of producing heat. 9. Mention some of the effects of heat upon matter. THE IMPORTANT FORMS OF ENERGY AND MOTION 43 10. What is the boiling point of any liquid ? 11. If a certain gas measures 273 volumes at 20° C, how much will it measure at 22° C? 12. A volume of a certain gas being 1 liter under the pressure of 1 atmosphere, what will be its volume under the pressure of 2 atmospheres ? 13. If a given mass of gas occupies 10 cubic centimeters at 0° C, how many cubic centimeters will it occupy at 212° F.? 14. If a given mass of gas occupies 50 volumes under 760 millimeters pressure, how many volumes will it occupy under 756 millimeters pressure ? 15. One liter of oxygen at 0° 0. and under 760 millimeters pressure weighs 1.43 grams. What is the weight of two liters of oxygen at 16° C. under 750 millimeters pressure? 16. One liter of carbon dioxide at 0° 0. under the pressure of one atmosphere weighs 1.9657 grams. What is the volume of 10 kilograms of 002 at 8° C. under a pressure of 4 atmospheres ? 17. State the law of Mariotte. 18. What is meant by latent heat ? 19. How can steam be heated to 200° 0.? 20. What form of molecular attraction in a solid must be overcome when that solid is dissolved in a liquid ? 21. How would you aid the solution of a gas in a liquid ? 22. What is commonly meant by the term solution ? 23. Does increased temperature always aid solution ? 24. What is the coefficient of solubility of a substance of which 60 grams can be dissolved in 300 grams of water at 15° C? 25. What are the most common solvents in pharmacy and chemistry ? 26. What is the difference between a hygroscopic and a deliquescent substance ? 27. What is meant by the expression diffusion of gases 9 44 A CORRESPONDENCE SCHOOL IN PHARMACY 28. Why is it necessary to protect medicinal substances from light ? 29. Define chemical energy. 30. Does heat aid or oppose chemical attraction ? 31. Is chemical attraction aided or opposed by light and by electricity? 32. Which form of attraction will cause the greater changes in matter, atomic attraction or molecular attraction ? 33. What produces combustion ? LESSON FOUR To the Student: The last two lessons have been concerned with the elements of physics. We now leave for a time that subject and take up the elements of chemistry. The next few lessons treat of the theory of chemistry and may seem somewhat obscure at first, but if you will read them carefully and weigh each statement, the meaning will doubtless appear to you. If the course of reasoning does not then seem clear, you can wait with the confident expectation that the subject will become clearer in subsequent lessons. Every new sub- ject has a vocabulary and language of its own, which for a time is difficult to the beginner, but by constant use of the terms he becomes familiar with them and is able to reason with greater ease and accu- racy. It is not expected that you will learn the text verbatim, except in the case of certain rules and principles which are italicized to attract your attention. Such, for instance, are the Law of Definite Pro- portions and Avogadro's Law, both of which you will find stated in the sixth lesson. The table of elements given in Section 122 is not to be committed to memory, though the names, symbols and atomic weights of the principal elements should be familiar. What these are you will learn from the frequency with which they are mentioned in the text. If you find yourself frequently referring to the table for the symbols and atomic weights of any given element, that should be sufficient hint to learn the facts relating to that element. VI The Chemical Elements 121. The classification of the elements into metals and non-metals has been referred to. But some elements possessing physical properties character- istic of the most pronounced metals have chemical properties 45 46 A CORRESPONDENCE COURSE IK PHARMACY such as strikingly characterize non-metallic elements, and a few elements partake more or less of the properties of both metals and non-metals, physically as well as chemically. 122. The following list includes the known elements (1905), a few of which have been so recently discovered and are so rare and costly that their properties have not yet been thoroughly studied. All elements are represented by specific symbols derived from their latinic or other names. These symbols are used for the purpose of constructing formulas representing the composition and structure of chemical compounds. The names of the most important elements contained in common substances, including those of medicinal value, are printed in heavy-faced type. The others are comparatively rare or economically unimportant. The names in the second column are in most cases coined words which are not Latin but simply latinic in form. TABLE OF THE CHEMICAL ELEMENTS WITH THEIR ATOMIC WEIGHTS •>& •% Elements thus marked are both physically and chemically non- metallic. •£• Elements which exhibit some of the physical properties of metals but which resemble the non-metallic elements in their chemical behavior. + Elements which are both physically and chemically metallic in their properties and behavior. Elements which are not known to enter into any chemical com- bination are printed in italics. Approximate Common Name. Latinic Name. Symbol. Relative Weight of the Atom. (Atomic Weight.) Aluminum + Aluminum Al 27 Antimony •>£• Antimonum or Stibium Sb 120 Argon Argonum A 39? Arsenic •>& Arsenum As 75 Barium + Barium Ba 137 Beryllium + Beryllium Be 9 THE CHEMICAL ELEMENTS 47 TABLE OF THE CHEMICAL ELEMENTS— Continued. Common Name. Latinic Name. Symbol.. Approximate Relative Weight of the Atom. (Atomic Weight.) Bismuth + , Boron 2g •><• Bromine •% •• Cadmium + Csesium + Calcium + Carbon ■% •>£ Cerium + Chlorine ■& •% Chromium + Cobalt + Columbium + Copper + Erbium + Fluorine ■■ %• Gallium + Germanium + Gold + Helium Hydrogen •}& •>£• Indium + Iodine $£■ •& Iridium + Iron + Krypton Lanthanum + Lead + Lithium + Magnesium + Manganese + Mercury + Molybdenum + Neodymium 4 Neon Nickel + Nitrogen •& •& Osmium + Oxygen •)£ •)£ Palladium + Phosphorus -)j$ •*• Platinum + Pollonium + Potassium + Praseodymium + Bismuthum Borum Bromum Cadmium Csesium Calcium Carboneum Cerium Chlorum Chromium Cobaltum Columbium Cuprum Erbium Fluorum Gallium Germanium Aurum Helium Hydrogenium Indium Iodum Iridium Ferrum Kryptum Lanthanum Plumbum Lithium Magnesium Manganum Hydrargyrum Molybdenum Neodymium Neum Niccolum Nitrogenium Osmium Oxygenium Palladium Phosphorus Platinum Pollonium Potassium or Kali Praseodymium Bi B Br Cd Cs Ca C Ce CI Cr Co Cb Cu Er F Ga Ge Au He H In I Ir Fe Kr La Pb Li Mg Mn Hg Mo Nd Ne Ni N Os O Pd P Pt Po K Pr 208 11 80 112 133 40 12 140 35.5 52 59 94 63.5 166 19 70 72 197 4 1 114 126.5 193 56 82 138 207 7 24.5 55 200 96 143 20 58.5 14 191 16 106 31 195 ? 39 140.5 48 A CORRESPONDENCE COURSE IN" PHARMACY TABLE OF THE CHEMICAL ELEMENTS— Continued. Approximate Common Name. Latinic Name. Symbol. Relative Weight op the Atom. (Atomic Weight.) Radium + Radium Ra 227 Rhodium + Rhodium Rh 103 Rubidium -f Rubidium Rb 85.5 Ruthenium + Ruthenium Ru 101.5 Samarium + Samarium Sm 150 Scandium + Scandium Sc 44 Selenium %< •>£ Selenium Se 79 Silicon j& 5& Silicium Si 28.5 Silver + Argentum Ag 108 Sodium + Sodium or Natrium ' Na 23 Strontium + Strontium Sr 88 Sulphur •% X Sulphur S 32 Tantalum + Tantalum Ta 183 Tellurium $£ Tellurium Te 127 Terbium + Terbium Tb 160 Thallium + Thallium Tl 204 Thorium + Thorium Th 233 Tin + Stannum Sri 118.5 Titanium + Titanium Ti 48 Tungsten + Wolframium W , 184 Uranium + Uranium U 240 Vanadium + Vanadium V 51.5 Xenon Xenum X 128 Ytterbium + Ytterbium Yb 173 Yttrium + Yttrium Yt 89 Zinc + Zincum Zn 65.5 Zirconium + Zirconium Zr 90.5 All the elements marked with 5K- or with X % can combine directly with hydrogen. They are chemically non-metallic elements. Elements marked + do not combine directly with hydrogen, although some of them form alloys with it. Neon, argon, krypton and xenon are gaseous elements recently discovered in the atmosphere; all efforts so far made to cause these elements to enter into chemical combination with any other elements have been unsuc- cessful. Oxygen and fluorine combine with hydrogen but not with each other. All elements can be directly united to oxygen THE CHEMICAL ELEMENTS 49 except fluorine and the four elements named in the preced- ing paragraph. 123. State of Cohesion of the Elements. All of the ele- ments enumerated in the preceding table are solids at ordinary temperatures, with the following exceptions : Mer- cury and bromine are liquids; argon, chlorine, fluorine, helium, krypton, neon, nitrogen, oxygen, xenon and hydro- gen are gases. 124. Colors of the Elements. The metals are generally opaque and white with or without a hue of grayish, bluish or reddish; but gold is yellow, barium and calcium are yellowish, copper is reddish. Bismuth displays variegated hues of purplish, while its general color is reddish-white. Of the non-metallic elements boron is black; carbon is either black, as in coal and graphite, or colorless, as in diamond; iodine is purplish-black; phosphorus is a White waxy substance or a dark red powder; selenium, red or black; silicon, brown or gray; sulphur, pale yellow, amber, dark brown, or nearly milk-white; bromine is a brown-red liquid; hydrogen, oxygen, nitrogen, argon, krypton, neon and xenon are colorless gases; chlorine is a greenish gas; and fluorine greenish-yellow. 125. Luster. All the metals possess a peculiar luster which in many cases can be greatly heightened by polishing. The only non-metallic elements that have a luster approach- ing that of metals are iodine in crystals and carbon in the form of graphite. The luster of the diamond is quite different from and far surpasses that of the metals. 126. The non-metallic elements never possess tenacity, ductility or malleability. Most of the metals exhibit one or the other of those properties. 127. Density. The specific weights of the five metals called lithium, sodium, potassium, rubidium and cassium range from 0.6 to 1.5; those of the metals called beryllium, 50 A CORRESPONDENCE COURSE IN PHARMACY magnesium, calcium, strontium and barium from 1.6 to 4; and those of the metals aluminum, scandium, yttrium, titan- ium and zirconium from 2.5 to 4. The specific weights of all other metals are higher than 5, ranging from 5.5 to 22.42. The specific weights of all physically non-metallic elements are below 5. 128. Fusibility. All metals are fusible. Of the non- metallic elements one is liquid and ten are gases. Sulphur, selenium, phosphorus and iodine are readily fusible. Carbon, boron and silicon are infusible. 129. Volatility. Of the physically metallic elements only mercury, potassium, sodium, magnesium, zinc, cadmium and arsenic may be readily distilled; and antimony and tellu- rium can be distilled with a current of hydrogen. The non-metallic elements that are not gaseous at ordinary temperatures can all be readily vaporized except carbon, boron and silicon. 130. Solubility in common solvents. All metals are absolutely insoluble in water, alcohol, ether, chloroform, glycerin, benzin, carbon disulphide, volatile oils and fixed oils. Chlorine and iodine are slightly soluble in water ; bromine more so. Iodine is soluble in alcohol, glycerin, chloroform, liquid hydrocarbons, carbon disulphide, volatile oils and fixed oils. Phosphorus is soluble in chloroform, ether, absolute alcohol, carbon disulphide and fixed oils. Sulphur dissolves in chloroform, benzine, carbon disulphide, oil of turpentine and fixed oils. 131. Metals are usually good conductors of heat and of electricity. The non-metallic elements are very feeble con- ductors. 132. Chemical behavior of metals and non-metals. The metals form various solutions and alloys with each other. Gold and several other metals dissolve in mercury at ordinary THE CHEMICAL ELEMENTS 51 temperatures. Many metals can be dissolved in each other when melted. Sometimes the combinations effected may be crystallizable bodies containing the component metals , in definite proportions corresponding to their atomic weights. But these combinations or alloys are decidedly metallic, retaining in a high degree the characteristics of the metals of which they are constituted. Hence it may be concluded that the combinations formed by the metals with each other are not true chemical compounds, but only solutions. The compounds formed by non-metallic elements with each other or with metals are strikingly different. They are countless, and they rarely resemble in any respect or degree their component elements. Thus the reddish metal copper combines with the colorless gas oxygen, forming a black powder called copper oxide; the brilliant, silver-white, liquid metal mercury combines with the colorless oxygen to form a red, or yellow, or black oxide, and with yellow sulphur to form a red or a black sulphide ; sulphur combined with its own weight of oxygen forms a colorless gas of an irritating odor, but with one and one-half times its weight of the gaseous oxygen it forms an odorless white solid; the three colorless gases nitrogen, hydrogen and oxygen form a white solid called ammonium nitrate; and the elements carbon, hydrogen, oxygen and nitrogen form innumerable compounds of a great variety of properties. Test Questions It will probably not be necessary for us to call your attention again to the form of your paper. Let it be understood that unless you are specifically directed to change your plan, you are to continue in that which has been prescribed for you. If the questions seem to call for any explanation, you will find that explanation at the beginning of the questions. 1. About how many metals are known and about how many non-metallic elements ? 52 A CORRESPONDENCE COURSE IN PHARMACY 2. What are the symbols for lead, antimony, mercury, potassium, silver, sodium and tin ? 3. What is the difference between a chemically metallic element and a chemically non-metallic element ? 4. Mention six elements which at ordinary temperatures are gases. 5. What elements are liquid at ordinary temperatures ? 6. Mention the most striking- physical properties by which metals differ from non-metallic elements. 7. Do you know of any non-metallic elements having specific weights between 6 and 10 ? 8. Can you mention some non-metallic elements which are not fusible ? 9. Mention some that are not volatile. 10. Are any of the metals soluble in each other, and if so, what are such solutions called ? 11. How many of the metals combine chemically with oxygen ? How many of them combine with hydrogen ? 12. How many of the non- metallic elements combine