LIBRARY 
 
 OF THE 
 
 UNIVERSITY OF CALIFORNIA. 
 
 OIFT OF 
 
 PROF, W,B, RISING 
 
 Class 
 
LABORATORY EXERCISES 
 
 WITH 
 
 OUTLINES FOR THE STUDY OF 
 CHEMISTRY 
 
 TO ACCOMPANY ANY ELEMENTARY TEXT 
 
 BY 
 
 H. H. NICHOLSON 
 
 Professor of Chemistry in the University of Nebraska 
 
 SAMUEL AVERY 
 
 Professor of Chemistry in the University of Idaho 
 
 
 NEW YORK 
 
 HENRY HOLT AND COMPANY 
 
 1899 
 

 Copyright, 1899, 
 
 BY 
 
 HENRY HOLT & CO. 
 
 ROBERT DRUMMOND, PRINTER, NEW YORK 
 
PREFACE. 
 
 THE primary object of the authors in preparing this 
 book is to place in the hands of the science teachers 
 in the State a laboratory manual adapted to the 
 average high-school requirements. In it we have 
 endeavored to emphasize the value of laboratory in- 
 struction in the laboratory. 
 
 The aim is to give the student facts, practically of 
 his own finding, before a discussion and correlation 
 of these facts. Our experience in teaching has led us 
 to the conclusion that to reach the best results a 
 student of chemistry must first be given experimental 
 work. In this way his interest is sufficiently aroused 
 to hear with profit descriptive lectures, or to read with 
 some attention the discussion of facts and principles 
 as found in elementary text-books. To this end he is 
 carefully guided in his experimental work, after which 
 he is expected to study the subject of his experiment 
 in one or more of the texts referred to at the end of 
 each exercise. 
 
 These texts are not necessarily the best that might 
 be given, but they are in many cases the only ones 
 available to the pupil. They are in all cases those 
 found to be at hand in class use or otherwise in the 
 high schools of this State. 
 
 In all cases the references themselves are to the 
 specific subject under investigation. 
 
 It is not intended that this manual should take the 
 
 237442 in 
 
iv PREFACE. 
 
 place of any of the many excellent text-books now in 
 use, but rather that it shall supplement and make 
 more useful those now in the hands of the pupils or 
 in the school libraries. 
 
 The authors' acknowledgments are due to Mr. 
 Jesse E. Beans of Omaha for his efficient service in 
 preparing the illustrations. We would also express 
 our thanks to Dr. John White of this university for 
 
 valuable suggestions. 
 
 THE AUTHOES. 
 UNIVERSITY OF NEBRASKA, 
 June 10th, 1899. 
 
ABBEEVIATIONS. 
 
 THE abbreviations calling for explanation are as 
 follows : 
 
 cc. cubic centimeter. grin. gram. 
 
 cm. centimeter. mm. millimeter. 
 
 Under " References ": 
 
 Clk. Elements of Chemistry, by F. W. Clarke. 
 New York : American Book Com- 
 pany. Date of copyright 1884. 
 
 Cly. New Text-book of Chemistry, by LeRoy 
 C. Cooley. New York : American 
 Book Company. Date of copyright 
 1881. 
 
 B. (Briefer Course.) An Introduction to 
 
 the Study of Chemistry, by Ira 
 Bemsen. New York : Henry Holt 
 and Company. Date of copyright 
 1893. 
 
 S. Elements of Inorganic Chemistry, by 
 
 James H. Shepard. Boston : D. C. 
 Heath and Company. Date of copy- 
 right 1885. 
 
 S. andL. An Elementary Manual of Chemistry, 
 by F. H. Storer and W. B Lindsay. 
 
ABBREVIATIONS. 
 
 New York : American Book Com- 
 pany. Date of copyright 1894. 
 W. Elements of Chemistry, by Rufus P. 
 
 Williams. Boston : Ginn and Com- 
 pany. Date of copyright 1897. 
 
SUGGESTIONS. 
 
 A NUMBER of carefully selected reference books 
 should be placed in the school library. The following 
 are especially recommended : 
 
 Inorganic Chemistry (Advanced Course), by Ira 
 
 Remsen. Henry Holt and Company, New York. 
 
 General Inorganic Chemistry, by Paul C. Freer. 
 
 Allyn and Bacon, Boston. 
 Organic Chemistry, by Ira Remsen. D. C. Heath 
 
 and Company, Boston. 
 
 Treatise on Chemistry, by Koscoe and Schor- 
 lemmer. Volumes I and II. D. Appleton and 
 Company, New York. 
 
 The articles on chemical topics in the " Britannica " 
 will be found especially valuable. The lives of famous 
 investigators may be studied in connection with their 
 discoveries, thus : 
 
 In connection with The life of 
 
 Oxygen < Priestley. 
 
 Chlorine Scheele. 
 
 Air Cavendish. 
 
 Atomic Weights Berzelius and Stas. 
 
 Atomic Theory . . . . , Dalton. 
 
 Combustion Lavoisier. 
 
 The Alkali Metals Davy. 
 
 vii 
 
TO THE PUPIL. 
 
 WOEK independently. You are not concerned with 
 what your fellow student is doing. 
 
 Do not talk, except with your instructor about your 
 work. 
 
 Do not ask questions of your instructor until you 
 have tried to answer your questions for yourself. 
 
 Keep in a note-book, especially reserved for this 
 use, an accurate record of your laboratory work. 
 Record your observations when you make them, not 
 from memory afterwards. 
 
 Do not hurry. 
 
 Keep the apparatus clean. 
 
 Work cautiously, using small quantities of re- 
 agents ; avoid inhaling poisonous gases, and be espe- 
 cially careful to avoid getting acids, alkalies, or any 
 other corrosive or poisonous substance into the eyes. 
 
 viii 
 
CONTENTS. 
 
 PAGE 
 
 ABBREVIATIONS v 
 
 SUGGESTIONS vii 
 
 To THE PUPIL viii 
 
 THE NON-METALLIC ELEMENTS. 
 
 EXERCISE 
 
 1. Preliminary Chemical Manipulation 3 
 
 2. Physical Changes and Chemical Changes 7 
 
 3. Conditions under which Chemical Changes take place 9 
 
 4. Elements. Mixtures and Compounds 11 
 
 5. Some Chemical Terms 13 
 
 6. Oxygen : Preparation and Physical Properties 15 
 
 7. Chemical Properties of Oxygen. Problems 18 
 
 8. Hydrogen: Usual Method of Preparation and Characteristic 
 
 Properties 21 
 
 9. Hydrogen continued 24 
 
 10. Valence 27 
 
 11. Water 30 
 
 12. Chlorine 34 
 
 13. Hydrochloric Acid 36 
 
 14. Classification of Certain Compounds 39 
 
 15 Nitrogen 42 
 
 16. Ammonia 44 
 
 17. NitricAcid 46 
 
 18. Compounds of Oxygen and Nitrogen 49 
 
 19. Carbon 52 
 
 20. Compounds of Carbon and Oxygen , . 55 
 
 21. Flames 58 
 
 22. Bromine 60 
 
 23. Iodine 63 
 
 24. Fluorine f 66 
 
 25. Sulphur 68 
 
 26. Sulphides 70 
 
 27. Sulphur Compounds containing Oxygen , . 73 
 
 ix 
 
VOATENT& 
 
 EXERCISE PAGE 
 
 28. Phosphorus 75 
 
 29. Arsenic 78 
 
 30. Silicon. Boron. Review of Non-metals 80 
 
 THE MORE IMPORTANT METALS. 
 
 31. The Alkali Metals 85 
 
 82. Compounds of the Alkaline Earths 88 
 
 33. Magnesium, Zinc, Cadmium, and Mercury 91 
 
 34. Copper, Silver, and Gold 94 
 
 35. Aluminium 96 
 
 36. Tin and Lead 98 
 
 37. Chromium 100 
 
 38. Manganese... 102 
 
 39. Iron, Cobalt, Nickel, and Platinum 104 
 
 SOME FAMILIAR HYDROCARBONS AND THEIR 
 DERIVATIVES. 
 
 40. Some Hydrocarbons 109 
 
 41. Some Halogen Derivatives of the Hydrocarbons Ill 
 
 42. Alcohol 113 
 
 43. Some Fatty Acids 116 
 
 44. Some Familiar Carbohydrates 118 
 
 45. A Few Aromatic or Benzene Derivatives 121 
 
 APPENDIX. 
 
 Information for Schools needing Equipment for Teaching 
 
 Chemistry 125 
 
THE NON-METALLIC ELEMENTS. 
 
EXERCISE 1, 
 
 PRELIMINARY CHEMICAL MANIPULATION. 
 
 Select a sound cork and a sharp borer. Press the 
 small end of the cork firmly against a block of soft 
 wood. Place the borer in the position shown in Fig. 1, 
 and cut a hole through the cork by twisting the borer 
 back and forth, applying at the same time a gentle 
 downward pressure. 
 
 A section of a properly bored cork will appear as in 
 
 FIG. 1. 
 
 FIG. 3. 
 
 Fig. 2 ; when the hole is punched instead of bored the 
 hole will appear as Fig. 3. 
 
 A hole can also be bored to advantage as follows : 
 Proceed as just directed till the borer has cut its way 
 about half through the cork, then remove borer, punch 
 out the little cylinder of cork from the borer-tube, and 
 bore from the other end of the cork. A little practice 
 
 3 
 
4: THIS NON-METALLIC ELEMENTS. 
 
 will enable you to strike the first hole, thus forming a 
 single boring through the cork. 
 
 To fit a piece of glass tube into a cork, proceed as 
 follows : Select a borer a trifle smaller than the tube 
 that you wish to use. If no borer of the right size is 
 at your disposal, select a smaller one and enlarge the 
 hole with a round file. Now insert, by pressure and 
 rotation, a tube which has been prepared according to 
 directions to be found in the next paragraph. 
 
 Make a file-mark on a piece of glass tube where you 
 wish to break it (a few inches from the end). Hold 
 the tube as shown in Fig. 4, and break by pulling apart, 
 
 FIG. 4. 
 
 at the same time bending slightly downward. The 
 ends of the tube will now be found sharp, and must be 
 rounded by rotating in the flame of a burner. Take 
 care in rounding to heat till the glass just softens, and 
 to withdraw from flame before tube begins to melt. 
 
 For practice insert three tubes into a cork of about 
 2 inches diameter, as shown in Fig. 5, and submit to 
 your teacher for approval. 
 
 Points to be observed : (1) The tubes must fit tightly. 
 (2) The tubes must be parallel. 
 
 To fit a cork into a flask (or bottle), proceed as fol- 
 lows : Select a cork of such size that the diameter, at 
 the small end, is just a little smaller than the mouth 
 
PRELIMINARY CHEMICAL MANIPULATION. 
 
 of the flask. Soften the cork by rolling between a 
 piece of board and the work-desk as shown in Fig. 6. 
 
 FIG. 5. 
 
 FIG. 6. 
 
 Use considerable pressure and roll for about a minute 
 (the cork may be placed on the floor and rolled with 
 the sole of the shoe). 
 
 For bending glass tubing the ordinary laboratory 
 burner will not answer. The best results are obtained 
 from a gas-burner. If the laboratory is not supplied 
 with gas, use an ordinary kerosene lamp without the 
 chimney For practice, hold a piece of fairly thick- 
 walled tube of 3 to 5 mm. in diameter outside measure 
 (j. to T 3 ^ inch) in the position shown in Fig. 7, Rotate 
 
 FIG. 7. 
 
 FIG. 8. 
 
 FIG. 9. 
 
 the tube, and when sufficiently hot bend to the desired 
 angle. Now bend a tube as shown in Fig. 8, and show 
 to your teacher for approval. 
 
6 
 
 THE NON-METALLIC ELEMENTS. 
 
 Points to be observed : (1) There must be no marked 
 contraction at the bend. (2) The arms must be in the 
 same plane and at right angles. 
 
 Fig. 9 represents a piece of tube bent in a Bunsen 
 or alcohol burner. 
 
 It is often necessary to draw out glass tubing to a 
 smaller bore. For this purpose the tube is rotated 
 
 in the flame of the burner 
 till the glass softens. Now 
 remove from the flame and 
 pull the tube to the desired 
 bore. 
 
 When you can successfully 
 follow directions up to this 
 point set up a wash-bottle as 
 shown in Fig. 10. 
 
 Use a 500-cc. flask and 3 to 
 5 mm. diam. glass tube. The 
 wash-bottle is to be filled 
 with distilled water and re- 
 served for future use. 
 L., pp. 395-398 and 406-497 ; 
 
 FIG. 10. 
 
 References : S. 
 W., pp. 384-388. 
 
 and 
 
EXERCISE 2. 
 
 PHYSICAL CHANGES AND CHEMICAL CHANGES. 
 
 EXPLANATION : Physical changes do not affect the 
 composition of substances. Chemical changes result 
 in the formation of new substances. 
 
 In the following experiments, ()-(/), show when 
 chemical and when physical changes take place. 
 
 (a) Hold by means of the tongs a piece of platinum 
 wire in the flame till it glows. Cool and examine. 
 
 (&) Try to repeat the same experiment, using mag- 
 nesium ribbon instead of the platinum wire. 
 
 (c) Put a piece of tin (J grm.) into a test-tube and 
 heat till the glass begins to be red. Cool and examine. 
 
 (d) Heat a little sugar in the same way. 
 
 (e) Procure a piece of Iceland spar, weighing about 
 1 grm. Note its appearance and form, especially the 
 angles. Is it soluble in water ? Now lay the piece on 
 the bottom of an inverted mortar and strike with the 
 pestle, breaking the piece into fragments. Examine 
 the fragments with a hand-lens, noting the form as 
 before. 
 
 (/) Put the fragments obtained in the last experi- 
 ment into an evaporating-dish and add a few drops of 
 dilute hydrochloric acid. Warming hastens the re- 
 action. When action ceases add a few more drops of 
 acid, repeating the process till a further addition of a 
 drop of the acid produces no effect. The spar should 
 be entirely dissolved. Now place the evaporating-dish 
 
 7 
 
8 THE NON-METALLIC ELEMENTS. 
 
 on a wire gauze supported by the ring-stand, and heat 
 cautiously till all of the liquid is driven off. The 
 evaporation should be carried out under the hood, or 
 where the draft is good. Examine the residue. Is it 
 Iceland spar ? Is it soluble in water ? 
 
 References : Clk., pp. 1, 2 ; Cly., pp. 1-3 ; R, pp. 1-3 ; 
 S. and L., pp. 7, 8 ; W., pp. 1, 2. 
 
EXERCISE 3. 
 
 CONDITIONS UNDER WHICH CHEMICAL CHANGES TAKE 
 PLACE. 
 
 In this exercise point out the conditions as heat- 
 ing, bringing into contact, submitting to the action 
 of the light, dissolving, etc. under which chemical 
 changes are produced. 
 
 (a) Heat a little potassium chlorate (J grm.) in a 
 dry test-tube, and when the molten substance seems 
 to boil, insert a glowing not a flaming splinter of 
 wood into the test-tube. 
 
 (b) Place a little tin (1 grm.) in a beaker and add 
 1 cc. concentrated nitric acid. 
 
 (c) Place in the mortar a crystal of potassium chlo- 
 rate as large as a grain of wheat, and in contact with 
 it an equal amount of sulphur. Now protect the hand 
 with a towel or glove, and grind the two substances 
 vigorously together. 
 
 (d) Procure from your teacher a piece of " blue- 
 print " paper (about 1 by 2 inches) that has not been 
 exposed to strong light. Divide it into halves and 
 place one in the direct sunlight for fifteen minutes. If 
 the day is dark, leave it exposed in the window till 
 your next period ; the other half is to be kept in the 
 dark (between the leaves of a book). After the one 
 piece has been sufficiently exposed t'o the light, put 
 both pieces in water to dissolve out any unchanged 
 coloring matter. Compare the color of the two pieces. 
 
 9 
 
10 THE NON-METALLIC ELEMENTS. 
 
 (e) Grind together in a mortar equal quantities 
 (J grin, each) of sodium bicarbonate and tartaric acid. 
 Does any change take place ? Now place the mixture 
 in a test-tube and add a little water. What do you 
 observe ? 
 
 (/) Describe the application of electricity in pro- 
 ducing chemical change. Refer to your text-book for 
 the answer to this question. 
 
 References : Clk., pp. 5, 6, 36, 37 ; Cly., pp. 4-7 ; E. ? 
 pp. 4-7. 
 
EXERCISE 4. 
 
 ELEMENTS, MIXTURES, AND COMPOUNDS. 
 
 In this exercise roll sulphur, not flowers of sulphur, must be used. 
 The iron should be "iron reduced by hydrogen." Do not use iron 
 filings. 
 
 (a) Take a few pieces of roll sulphur and carefully 
 study its physical properties. Hold a fragment on a 
 piece of wire in the flame of the burner and note the 
 color of the sulphur flame, and the odor given off. 
 Now powder the pieces in a mortar. How can you 
 show that the powdered substance is still sulphur ? 
 
 (b) Put a little of the powdered sulphur into a dry 
 test-tube and add to it 2 or 3 cc. of carbon disulphide. 
 (Caution : Keep carbon disulphide away from flames, 
 as it is very inflammable.) What becomes of the sul- 
 phur in the test-tube ? Pour the liquid in the tube 
 into a watch-glass and let stand for a short time. 
 What takes place? Explain these phenomena. 
 
 (c) Treat a little (J grm.) iron with carbon disul- 
 phide just as you did the sulphur. Is the iron solu- 
 ble? 
 
 Note. Do not be confused in your conclusions by traces of iron 
 that may be held in suspension, or by traces of sulphur that com- 
 mercial carbon disulphide often holds in solution. 
 
 Dust a little iron into the flame of the burner. What 
 do you notice? Is iron attracted by the magnet? 
 State all the points of difference that you have ob- 
 served between iron and sulphur. 
 
 You have now studied some of the properties of two 
 elements. What is an element? See text (index). 
 
 11 
 
12 TEE NON-METALLIC ELEMENTS. 
 
 (d) Grind together in a mortar 3 grms. of sulphur 
 with 5 grms. of the powdered iron. Does any change 
 take place ? Examine carefully with a magnifying-glass. 
 Can you see the iron or the sulphur? Spread out on 
 a sheet of paper a small portion and see if you can 
 separate the iron from the sulphur by passing the 
 magnet just above, not quite touching the thin layer 
 on the paper. Can you separate the iron from the sul- 
 phur by physical means ? 
 
 (e) Take another portion of the material prepared 
 in (d) and treat with carbon disulphide in a test-tube. 
 Put your thumb over the top of the tube and shake 
 the contents of the tube thoroughly, cork the tube and 
 let it stand quietly for a few minutes, then pour off 
 the liquid into a watch-glass, being careful not to dis- 
 turb the solid in the bottom. Let the watch-glass 
 stand until the liquid has evaporated. What remains? 
 How do you know ? What remains in the test-tube ? 
 How do you recognize it ? 
 
 (/) What have you accomplished in this experi- 
 ment? Take the rest of the material prepared in (d) 
 and put it in a dry test-tube ; heat strongly in a lamp- 
 flame> What takes place ? Break the tube and pul- 
 verize its contents in a mortar ; compare it with the 
 substances used in experiments (c), (d), and (e). Have 
 you now a chemical compound ? Why do you think so ? 
 
 Write a resume of (a) to (/) inclusive, telling what 
 classes of substances have been used ; what facts 
 have been observed and your explanation of these 
 facts. 
 
 References: Clk., pp. 8, 9 to Table 1 ; Cly., pp. 8, 9 
 to exercises ; E., pp. 10, 12 ; S., pp. 8, 11 ; S. and L., 
 pp. 9, 10 ; W., pp. 5, 6 to Sec. 8. 
 
EXERCISE 5. 
 
 SOME CHEMICAL TERMS. 
 
 This exercise contains no laboratory work. It is intended to review 
 the preceding exercises, and to familiarize the student with certain 
 chemical expressions that occur in the exercises that follow. The 
 knowledge necessary to answer the questions may be derived from 
 previous study, from explanations from the teacher, and from any 
 work on chemistry in the school library. 
 
 Name five instances of physical change and as many 
 instances of chemical change that you have noticed 
 outside of the laboratory. 
 
 Can the same force under different conditions pro- 
 duce both physical changes and chemical changes ? 
 
 Can a chemical change (as the burning of oil in the 
 lamp) produce a physical change ? 
 
 What do you understand by the terms: element; 
 compound; mixture? 
 
 What is meant by the terms : atom ; atomic weight; 
 molecule; molecular weight? 
 
 Explain in ordinary language the expression : 
 
 Fe + S = FeS. 
 
 If the relative weights of the atoms of iron and sul- 
 phur are as 56 : 32, how much of each will you have to 
 take to form eighty-eight pounds of iron sulphide? 
 eighty-eight grams ? eighty-eight tons ? 
 
 The weight relations expressed in the problem 
 depend on the law of the " Indestructibility of Mat- 
 ter." State this law. What is a natural law? 
 
 13 
 
i.4 THE NON-METALLIC ELEMENTS. 
 
 References (in addition to those given in Exercises 2, 
 3, and 4): Oik., pp. 10-13; Cly., pp. 10-15, 17-19; K, 
 pp. 16-19, 71, 76-82 ; S., pp. 14r-19 ; S. and L., pp. 
 26,27; W., pp. 16-18. 
 
EXERCISE 6. 
 
 OXYGEN : PREPARATION AND PHYSICAL PROPERTIES. 
 
 Preliminary Experiment. To collect a gas not soluble 
 in water proceed as follows : Pour water into a pneu- 
 matic trough till the water rises above the shelf. Fill 
 a bottle with water and cover with a piece of writing- 
 paper, taking care to exclude all air-bubbles. Now, 
 pressing the paper against the mouth of the bottle 
 with the fingers, place the bottle, mouth downward, in 
 the trough and withdraw the paper below the surface 
 of the water. Set the bottle entirely full of water 
 on the shelf of the pneumatic trough. (See position 
 of large test-tube in Fig. 11.) A tube is used to con- 
 duct the gas ink the bottle. Fill the bottle with ex- 
 haled breath by blowing through a tube. 
 
 Oxygen may be collected most conveniently by dis- 
 placement of water. 
 
 To prepare oxygen set up apparatus as shown in 
 Fig. 11. Place in the small test-tube a mixture of 
 equal weights of potassium chlorate and manganese 
 dioxide (2 grms. each ground together in a mortar), 
 and heat gently at first, gradually increasing the tem- 
 perature till the gas comes off freely. When this stage 
 is reached conduct the heating in such a way as to 
 secure a gradual evolution of gas. Hold the burner 
 in the hand and heat all parts of the mixture equally. 
 
 Collect two or three bottles of oxygen. When oxy- 
 gen ceases to come off or when your bottles are full 
 
 15 
 
16 
 
 THE NON-METALLIC ELEMENTS. 
 
 remove the delivery-tube at once from the test-tube 
 to prevent the water from drawing back into the test- 
 tube. 
 
 Made in this way oxygen looks cloudy on account 
 
 of impurities. These will nearly all dissolve out by 
 allowing the bottles to stand for fifteen minutes in the 
 trough. (Employ this time in writing up your notes 
 and in making a drawing of the apparatus used.) 
 
 Now place a piece of glass plate or pasteboard be- 
 low the surface of the water under the mouth of one 
 of the bottles and invert it. Insert a splinter with a 
 spark on the end. What takes place ? This is a test 
 for oxygen. 
 
 Try to determine whether oxygen is heavier or 
 lighter than air in the following way : A bottle with 
 its mouth downward, closed with a glass plate, is sud- 
 denly opened and at the same time a glowing splinter 
 is brought up into the mouth of the bottle from below. 
 
OXYGEN PHYSICAL PROPERTIES. 17 
 
 Another bottle with the mouth upward is uncovered 
 and a glowing splinter inserted from above. Does the 
 oxygen seem to fall to meet the spark or does it rise ? 
 Is the difference at all striking? 
 
 Has oxygen any odor, color, or taste ? 
 
 Oxygen may also be prepared by other methods, as 
 follows : 
 
 (a) Heat a little potassium chlorate and test as in 
 section (a) of Exercise 3. Does this or the method 
 last used seem to require the higher temperature ? 
 
 (b) Heat a little chromic acid in a test-tube and test 
 the escaping gas for oxygen. 
 
 (c) Prepare oxygen by heating mercuric oxide in the 
 following way : An ignition-tube containing a little of 
 the oxide is attached, by means of a short piece of 
 rubber tube, to a delivery-tube. The oxide is now 
 heated very gradually at first to avoid cracking the 
 glass, afterwards to a high temperature. After the 
 escape of a few bubbles (consisting of air) the oxygen 
 evolved is collected by displacement of water. Col- 
 lect in a test-tube and prove that you have obtained 
 oxygen. 
 
 Note. Small ignition-tubes may be made as follows: A piece of 
 tubing long enough for two ignition-tubes is rotated in the flame 
 till the heat gradually separates the tube into two parts of equal 
 length. The hot parts are protected from too-rapid cooling by cover- 
 ing with soot from the luminous flame of a gas-burner. (A kerosene 
 lamp with the chimney removed may be used instead of the gas 
 burner. 
 
EXERCISE 7. 
 CHEMICAL PROPERTIES OF OXYGEN. PROBLEMS. 
 
 In testing the action of gases care should be taken to prevent un- 
 necessary diffusion ; hence the bottles should be kept well covered 
 and the substances used in the tests should be introduced through 
 small openings. Solids may be conveniently introduced by means of 
 a deflagrating- spoon. Such a spoon may be made of crayon and wire 
 as shown in Fig. 12. 
 
 Oxygen unites with every other element except fluo- 
 rine ; hence it possesses great chemical activity. Is it 
 chemically active with most substances at 
 ordinary temperatures? To determine this 
 introduce into a bottle of the gas a small 
 piece of charcoal, and allow it to remain 
 several minutes. Do you notice any change ? 
 Why? Eepeat the same process, using a 
 small piece of sulphur. What is the result? 
 What do these experiments show ? Now set 
 IG fire to a piece of charcoal and allow it to 
 remain in the air for a few minutes ; then insert 
 it into a jar of oxygen. Is there any difference 
 in the manner in which it burns? What causes 
 this difference ? Repeat the process, using sulphur. 
 What do you observe? Are the products of com- 
 bustion the same when substances burn in air as 
 when they burn in pure oxygen ? Give reasons for 
 your answer. Heat the end of a picture-wire and dip 
 into flowers of sulphur. Set fire to the sulphur ad- 
 hering to the wire and insert into a bottle containing 
 
 18 
 
OXYGEN CHEMICAL PROPEETIES. 19 
 
 oxygen. Describe what takes place. What is the 
 nature of the substance formed ? Does the amount of 
 oxygen that can be procured from 1 grm. of potassium 
 chlorate ever vary ? 
 
 Does a given amount of mercuric oxide always yield 
 a definite amount of oxygen ? 
 
 What do you understand by the " law of definite 
 proportions " ? Explain the meaning of the expres- 
 sions : 
 
 KC1O 3 = KC1 + 3O. 
 HgO = Hg +0. 
 2CrO, = Cr a O, + 3O. 
 
 (1) How much oxygen can you get from 1 grm. of 
 mercuric oxide ? 
 
 Calculation : From the text-book you find that 
 oxj T gen and mercury have atomic weights of 16 and 
 200 respectively ; hence mercuric oxide has a molecu- 
 lar weight of 216. 
 
 HgO = Hg + O ; 
 216 = 200 + 16 ; 
 
 hence ^r^ = 7.41$ oxygen in mercuric oxide. 
 
 of 1 grm. 0.0741 grm. of oxygen. 
 Second calculation : 
 
 Molecular Weight. Atomic Weight. Weight in grms. Weight in grms. 
 
 HgO : O = Mercuric oxide : oxygen sought. 
 216 : 16 = 1 : ' x. 
 
 x = = 0.0741 grm. oxygen. 
 
20 THE NON-METALLIC ELEMENTS. 
 
 (2) How much mercury would be liberated in maL 
 ing 1 grm. of oxygen ? 
 
 (3) How much mercuric oxide would you have to 
 take to obtain 1 grm. of oxygen ? 
 
 Solve the three following by the formula : 
 
 KC1O S = KC1 + 30. 
 122.5 = 74.5 + 48. 
 
 (4) How much oxygen can you get from 1 grm. of 
 potassium chlorate ? 
 
 (5) How much potassium chloride (KC1) would be 
 left after driving off all the oxygen from 1 grm. of po- 
 tassium chlorate ? 
 
 (6) How much potassium chlorate will you have to 
 decompose in order to get 1 grm. of oxygen ? 
 
 References : Oik., pp. 24-31, 72-75 ; Cly., pp. 83-87; 
 E., pp. 20-36, 83-87 ; S., pp. 23-32 ; S. and L., pp. 
 15-18 ; W., pp, 19-25. 
 
EXERCISE 8. 
 
 HYDROGEN : USUAL METHOD OF PREPARATION AND CHAR- 
 ACTERISTIC PROPERTIES. 
 
 Fit a wide-mouthed bottle with a good cork, through 
 which is passed a thistle-tube and a delivery-tube. 
 See larger bottle in Fig. 13 (the smaller bottle is not 
 used in the first part of this exercise). Hydrogen is 
 the lightest substance known, hence it can readily pass 
 through parts of apparatus that are sufficiently tight 
 to contain other gases. The cork must be well rolled 
 and pressed very tightly into the neck of the bottle. 
 Rubber connections may be bound with a cord or with 
 fine wire. 
 
 Put about twenty-five grms. of granulated or sheet 
 zinc into the bottle ; replace the cork and tubes, tak- 
 ing care that the thistle-tube extends to within about 
 two mm. of the bottom of the bottle. Pour through 
 the thistle-tube dilute sulphuric acid, a few cc. at a 
 time in order that the evolution of gas may not be too 
 rapid. In case hydrogen is not at once generated 
 freely, add a little copper sulphate solution through 
 the thistle-tube. "When you think that all air has been 
 expelled from the apparatus collect several bottles of 
 the gas by displacement of water for use in the follow- 
 ing experiments : 
 
 (a) Thrust a glowing splinter upward into a bottle 
 of hydrogen. Does hydrogen burn at the mouth o t 
 the bottle ? Does it support combustion ? 
 
 21 
 
22 THE NON-METALLIC ELEMENTS. 
 
 (b) Allow a bottle to stand uncovered for one to two 
 minutes. Does it now contain hydrogen ? (Test with 
 spark.) Repeat the experiment holding the bottle 
 with its mouth downward. Does it now contain hy- 
 drogen ? 
 
 (c) Try to pour hydrogen up into a bottle in the fol- 
 lowing way: A bottle of hydrogen with its mouth 
 downward (closed) is held beside a bottle containing 
 air. Remove the plate from the mouth of the bottle 
 containing hydrogen and pour the gas up into the 
 other bottle. Does this bottle now contain hydrogen 
 (or a mixture of hydrogen and air) ? 
 
 If, now, the greater part of the zinc has dissolved, 
 empty out the contents of the generator and recharge. 
 When all air is expelled fill a toy balloon. Does the 
 balloon rise ? Why ? Allow the balloon to rise to 
 the ceiling. Does it fall after a time ? Why ? 
 
 What do you conclude from these experiments con- 
 cerning the lightness of hydrogen ? 
 
 Made in this way hydrogen has an odor due to im- 
 purities. Remove these by passing the gas through a 
 solution of potassium permanganate (one part to thirty 
 parts of water). See Fig. 13. 
 
 Collect a bottle of the pure gas and notice whether 
 it has any odor, color, or taste. 
 
 Fill a bottle one third full of water, close tightly 
 with the hand and place mouth downward on the shelf 
 of the pneumatic trough ; the bottle is now two thirds 
 full of air. Fill the remaining one third with hydro- 
 gen by displacement of the water in the bottle. Re- 
 move the bottle and apply a lighted splinter, keeping 
 the bottle well closed till the instant of ignition. This 
 experiment shows the explosive character of a mixture 
 of hydrogen and air. Before lighting a jet of hydro- 
 
HYDROGEN: CHARACTERISTIC PROPERTIES. 
 
 23 
 
 gen always collect a large test-tube of the gas by dis- 
 placement of water and apply a flame at the instant of 
 uncovering. If only a slight puff occurs and the gas 
 
 FIG. 13. 
 
 burns quietly, you can safely light the hydrogen as it 
 issues from the generator. Always make this test to 
 avoid dangerous explosions. Now remove the bottle 
 containing the permanganate solution and connect a 
 blowpipe with the delivery-tube of the generator at A 
 (Fig. 13). Light the hydrogen as it issues from the 
 opening in the end of the blowpipe. What is the 
 character of the flame ? Does it emit much light or 
 much heat? 
 
 Fill a beaker with water to keep the surface cool 
 and hold over the flame. What collects on the cool 
 glass ? What is formed when hydrogen burns ? 
 
 Eeserve the zinc solution in the generator for study 
 in the next exercise. 
 
EXERCISE 9. 
 
 HYDROGEN CONTINUED. 
 
 The bottle used in generating hydrogen in the last 
 exercise contains, besides undissolved zinc and im- 
 purities, zinc sulphate, either in solution or in the 
 form of a crystalline solid. If in solution, filter and 
 evaporate the clear filtrate on the water-bath to such 
 a degree of concentration that crystals will gradually 
 separate out on cooling (try two thirds former volume). 
 If, on the other hand, you find crystals in the bottle, 
 dissolve them by heating the 
 bottle and its contents in the 
 water-bath. Filter and without 
 concentration set aside to crystal- 
 lize. 
 
 The crystals consist of zinc sul- 
 phate crystallized with seven 
 molecules of water. Show them 
 to the instructor. (Note on fil- 
 tration. A - circular filter-paper 
 is folded into halves, then quar- 
 ters. It is now opened out into 
 a cone having an angle of 60. 
 Place it in a funnel and wet with 
 The paper should fit the funnel 
 
 FIG. 14 
 
 distilled water, 
 closely.) 
 
 Filtration is more rapid when a folded filter, as 
 shown in Fig. 14, is used. 
 
 24 
 
HYDROGEN CONTINUED. 2 5 
 
 Explain the meaning of the reaction : 
 
 Zn + H 2 S0 4 = ZnSO 4 + H a . 
 65+98 = 161 + 2. 
 
 Solve the following problems according to the above 
 reaction : 
 
 (1) How much hydrogen can you get using 100 
 grms. zinc ? 
 
 (2) How much sulphuric acid is required to dissolve 
 100 grms. zinc ? 
 
 (3) How much zinc and how much sulphuric acid 
 will you require to produce a gram of hydrogen ? 
 
 A liter (approximately a quart) of hydrogen weighs 
 .0896 grm. 
 
 (4) How many liters of hydrogen will be produced 
 in problem 3 ? 
 
 (5) How much zinc and how much sulphuric acid 
 would be required to produce a liter of hydrogen ? 
 
 Hydrogen can also be prepared by other methods. 
 (Perform experiments (a)-(d) in a test-tube and test 
 the escaping gas with a flame.) 
 
 (a) Treat a little zinc with hydrochloric acid. 
 
 (6) Treat a little iron with dilute sulphuric acid. 
 
 (c) Perform the same experiment using hydrochloric 
 instead of sulphuric acid. 
 
 (d) Treat aluminium ( grm.) with dilute sodium 
 hydrate solution and warm. 
 
 (e) Heat in a beaker a little water almost to boiling. 
 Now drop in a piece of sodium as large as a grain of 
 barley, and cover the beaker with a glass plate. "What 
 takes place ? Test the solution with red litmus paper. 
 Does it react the same as the sodium hydrate on your 
 
V6 TEE NON-METALLIC ELEMENTS. 
 
 desk ? Consult your text for symbols and write the 
 reaction between sodium and water. 
 
 References : Clk., pp. 14-23 ; Cly., pp. 60-69 ; B., 
 pp. 37-46 ; S., pp. 34-48 ; S. and L., pp. 34-43 ; W., 
 pp. 31-38. 
 
EXERCISE 10. 
 VALENCE. 
 
 You have already learned (Exercise 5) that the 
 hydrogen atom is taken as the unit in which atomic 
 and molecular weights are expressed. The hydrogen 
 atom also serves as the unit in which is expressed the 
 capacity that one atom has for combining with other 
 atoms. This capacity is called valence. 
 
 1 atom of chlorine unites with 1 atom of hydrogen 
 forming hydrochloric acid (HC1). Hence chlorine 
 has (in this instance) a valence of 1. 
 
 1 atom of oxygen unites with 2 atoms of hydrogen 
 forming water (H,O). Hence oxygen has a valence 
 of 2. 
 
 1 atom of zinc unites with 1 atom of oxygen forming 
 zinc oxide (ZnO). Oxygen has a valence of 2, hence 
 zinc has a valence of 2. Zinc reacts with sulphuric 
 acid liberating 2 atoms of hydrogen for every atom of 
 zinc that dissolves ; this also shows that zinc has a 
 valence of 2. 
 
 Lead forms with oxygen PbO and PbO 2 , hence lead 
 has a valence of 2 and of 4. 
 
 Atoms having a valence of 1 are said to be univa- 
 lent ; of 2, bivalent ; of 3, trivalent ; of i, quadrivalent; 
 of 5, quinquivalent. 
 
 The following list shows the usual valences of some 
 
 27 
 
THE NON-METALLIC ELEMENTS. 
 
 well-known elements. It will be seen that certain 
 elements are given in more than one column. This 
 shows that these elements have a varying valence. 
 
 Univalent. 
 
 Bromine Br. 
 
 Chlorine 01. 
 
 .Fluorine F. 
 
 Hydrogen H. 
 
 Iodine I. 
 
 Silver Ag. 
 
 Sodium Na. 
 
 Potassium K. 
 
 Quadrivalent. 
 
 Bivalent. Trivalent. 
 
 Calcium Ca. Aluminium Al. 
 
 Carbon C. Antimony Sb. 
 
 Copper Cu. Arsenic As. 
 
 Iron Fe. Boron B. 
 
 Lead Pb. Iron Fe. 
 
 Magnesium Mg. Nitrogen N. 
 
 Oxygen O. 
 
 Sulphur S. 
 
 Tin Sn. 
 
 Zinc Zn. 
 
 Quinquivalent. 
 
 Carbon C. Antimony Sb. 
 
 Lead Pb. Arsenic As. 
 
 Silicon Si. Nitrogen N. 
 
 Tin Sn. Phosphorus P. 
 
 Write the symbols of the following-named com- 
 pounds : 
 
 (1) lead iodides ; (2) potassium oxide ; (3) calcium 
 sulphide ; (4) magnesium iodide ; (5) tin bromides ; 
 (6) hydrogen chloride ; (7) aluminium chloride ; (8) 
 zinc sulphide ; (9) copper bromide ; (10) lead chlorides ; 
 (11) zinc oxide ; (12) silicon oxide ; (13) antimony 
 chlorides ; (14) carbon oxides ; (15) phosphorus chlo- 
 rides ; (16) sodium bromide ; (17) sodium sulphide ; 
 (18) sodium oxide; (19) calcium oxide; (20) arsenic 
 oxides ; (21) aluminium oxides ; (22 silver bromide ; 
 (23) boron oxide. 
 
VALENCE. 29 
 
 A knowledge of valence helps us 10 write the sym- 
 bols of compounds correctly. Example : To write the 
 symbol silicon fluoride, we consult the above table and 
 find that silicon has a valence of 4 ; fluorine of 1. 
 Hence the symbol is SiF 4 . 
 
EXERCISE 11. 
 WATER. 
 
 Water has the symbol H 2 O. Write the reaction that 
 takes place when hydrogen burns. How many grams 
 of hydrogen must you burn to produce a gram of 
 water ? How many liters of hydrogen ? How many 
 grams of oxygen will be consumed ? 
 
 (a) Distribution. 
 
 Heat in a dry test-tube a little wood. Try the same 
 experiment with a little bread ; with sugar. What 
 evidence have you that water is liberated in each 
 case? 
 
 (b) Solution in Water. 
 
 EXPLANATION : If you treat pure salt with water in 
 sufficient quantity, the salt disappears and you obtain 
 a liquid that looks like pure water. The taste shows 
 that salt is present in solution. If you add a crystal 
 of potassium permanganate to sufficient water, the 
 crystal disappears and you obtain a clear but highly 
 colored solution. The color shows that the perman- 
 ganate is present in the solution. On the other hand, 
 if you shake finely powdered chalk with water you ob- 
 tain a milky liquid which is not a solution since the 
 chalk is simply suspended in the water. In the same 
 way, oil and water, mixed, do not give a solution, as the 
 
 30 
 
WATER. 31 
 
 oil is simply suspended in, or floats on the surface of, 
 the Water. Alcohol, however, dissolves in water form- 
 ing a clear solution. Examples of solution : hard water, 
 all dilute liquid reagents, clear tea and coffee. Exam- 
 ples of substances suspended in liquids : milk, white- 
 wash, dirty water, muddy coffee. 
 
 Evaporate 25 cc. of " city " or well water, free from 
 suspended matter, in a clean evaporating-dish, just to 
 dryness. What evidence have you that the water held 
 solid matter in solution ? Repeat the experiment 
 using distilled water. Kesults ? Why do we use dis- 
 tilled water in the laboratory ? 
 
 (c) Conditions affecting Solution. 
 
 (1) State of Division. Place a crystal of copper sul- 
 phate (-J grm.) in a test-tube half full of water and 
 shake for several minutes or till the crystal nearly 
 dissolves. Eepeat using the same volume of water 
 and grm. finely pulverized copper sulphate. In 
 which case is solution the more rapid ? 
 
 (2) Temperature. Add 2 grms. ammonium chloride 
 to 5 cc. water. Shake for a few minutes. Is solu- 
 tion complete ? Now heat to boiling. What takes 
 place ? Allow to cool and note result. What effect 
 does heat have upon the solubility of most sub- 
 stances ? 
 
 (d) Saturated Solution. 
 
 This may be prepared as follows : Put 100 cc. of 
 water in a beaker and bring into solution as much 
 common salt as the water will dissolve. Make use 
 of what you have learned in the last section in regard 
 to state of division and temperature. When no more 
 
32 THE NON-METALLIC ELEMENTS. 
 
 of the salt will dissolve allow to cool to the tem- 
 perature of the room. A little salt separates out, 
 and you have a saturated solution. Filter from 
 undissolved salt, evaporate to one half the former 
 volume, and cool. What has separated out? What 
 must always take place (if no chemical change oc- 
 curs) when you concentrate a saturated solution ? 
 Filter the salt from the solution, dry on filter-paper, 
 and preserve for future use. 
 
 (e) Water of Crystallization ; Water-free Crystals. 
 
 EXPLANATION : Many substances unite with definite 
 amounts of water in the process of crystallization. 
 We cannot drive off this water without destroying the 
 form of the crystal. On the other hand, many sub- 
 stances crystallize without water. These substances 
 may, and commonly do, have adherent moisture on 
 the surface or even water enclosed mechanically in 
 the crystal, but this water has nothing to do with the 
 structure of the crystal and may be driven off without 
 affecting the crystal's form. 
 
 Heat a little (J grm.) pure dry salt in a test-tube and 
 note result. 
 
 Heat an equal amount of crystallized sodium sul- 
 phate in the same way. Which of these substances 
 contains water of crystallization ? 
 
 Try the same experiment with each of the follow- 
 ing : potassium chloride, copper sulphate, and cobilt- 
 ous chloride. Heat the last two substances gradu- 
 ally till the color just changes. Cool and add a 
 drop of water. Note all you observe and expiain 
 fully. 
 
WATER. 33 
 
 (/) Efflorescence. 
 
 Expose to the air a crystal of sodium sulphate in a 
 watch-glass. Examine after some time. Explain. 
 Bepeat with a crystal of sodium carbonate. 
 
 (g) Deliquescence. 
 
 Treat a small piece of calcium chloride and of po- 
 tassium hydrate as you did the substances in (/). 
 What do you observe in each case ? (Note. The time 
 required for any marked change in (/) and (g) will 
 depend upon the amount of moisture in the atmos- 
 phere. If the air is dry, breathe over the substances. 
 In damp weather set in direct sunlight, in closed 
 window.) 
 
 How can you find out whether a liquid holds a solid 
 in solution ? 
 
 Does a substance that is entirely insoluble have 
 any taste ? 
 
EXERCISE 
 
 CHLORINE. 
 
 All work with chlorine must be done under tlie hood. Avoid in- 
 haling the gas. 
 
 Put 25 grms. of manganese dioxide in a (250-cc.) 
 flask, fitted with a cork, a delivery-tube, and a 
 thistle-tube. See Fig. 15. Add 
 through the thistle-tube enough 
 concentrated hydrochloric acid to 
 cover the manganese dioxide, and 
 shake till you are sure that all of 
 the oxide is in contact with the 
 acid. Warm gently on a wire 
 gauze, taking care not to boil. 
 
 
 
 =#>m 
 
 Eeaction : MnO a + 4HC1 = 
 
 Mn01 
 
 2H 2 
 
 01,. 
 
 It 
 
 I 
 
 FIG. 15. 
 
 Collect several bottles for study 
 by displacement of air. Try to 
 collect one bottle by displace- 
 ment of water. Which is the 
 better way.? Why ? 
 
 (a) In one bottle place two 
 pieces of calico (preferably red), orte wet, and the 
 other dry ; a small piece each of written (ink) and 
 printed paper, both wet ; a wet .green leaf or flower. 
 Does moisture aid the bleaching action of chlorine ? 
 From which of the substances is the color discharged ? 
 Conclusion ? 
 
 (b) Dissolve the gas in another bottle by shaking 
 
 34 
 
CHLORINE. 35 
 
 with 20 cc. of water. Pour half of this solution into 
 10 cc. of a dilute solution of some vegetable color, as 
 indigo. Is the color discharged? Pour the rest of 
 the chlorine-water into a solution of potassium bi- 
 chromate. Does chlorine seem to have the same effect 
 on mineral as on vegetable colors ? 
 
 (c) Into another bottle of the gas sprinkle a little 
 powderecL. antimony. One atom of antimony (Sb) 
 unites with three atoms of chlorine. Write the re- 
 action. What is the name of the product formed ? 
 
 (d) Into another bottle of chlorine introduce a strip 
 of filter-paper that has been treated with a drop 
 of warm oil of turpentine. What takes place ? Tur- 
 pentine is composed of carbon and hydrogen. With 
 which of these elements has chlorine united ? 
 
 Other methods of making chlorine : 
 
 (1) Warm in a test-tube a very small amount of a 
 mixture of salt and manganese dioxide, with a few 
 drops of dilute sulphuric acid. Test the escaping 
 gas with a piece of wet calico. 
 
 (2) Warm a little potassium bichromate with con- 
 centrated hydrochloric acid, and test as in (1). 
 
 (3) Put 1 cc. water in a test-tube and add the same 
 amount of concentrated sulphuric acid. Treat a little 
 fresh bleaching-powder with this acid. What is 
 liberated ? 
 
 Will chlorine burn? Will it support combustion? 
 Is it soluble in water ? How is it prepared commer- 
 cially ? What are its uses ? 
 
 How much chlorine can be made from 60 grms. 
 salt ? How much manganese dioxide will be required ? 
 
 References : Clk., pp. 111-117 ; Cly., pp. 70-74; K., 
 pp. 95-100 ; S., pp. 92-96 ; S. and L., pp. 79-84 ; W., 
 pp. 202-207. 
 
EXERCISE 13. 
 
 HYDROCHLORIC ACID (HC1). 
 
 Add 30 cc. of concentrated sulphuric acid to 10 cc. of 
 water in a beaker. While the acid is cooling set up 
 apparatus as shown in Fig. 15, connect- 
 = ing at A the absorption apparatus 
 (Fig. 16) instead of the delivery-tube. 
 Put 20 cc. of water in the first, and 
 several times as much in the second, 
 bottle. The tubes should not quite 
 reach the surface of the water. Put 
 25 grms. salt in the flask, replace 
 stopper and tubes, and, when the ap- 
 paratus is in order, pour the sulphuric 
 acid through the thistle-tube and warm 
 16 S en ^y- When the gas comes off freely, 
 
 disconnect at A long enough to per- 
 form the following experiments : 
 
 (a) Blow across the tube where the gas is escaping. 
 What effect does the gas have on the moisture in your 
 breath? 
 
 (b) Test the escaping gas with a lighted splinter. 
 Does it burn ? Does it support combustion ? 
 
 (c) Does it affect red or blue litmus paper ? 
 
 (d) Put two or three drops of ammonia on filter- 
 paper and hold in the escaping gas. What happens? 
 
 Now connect a delivery-tube at A, as in Fig. 15, and 
 
 36 
 
HYDROCHLORIC ACID. 37 
 
 collect the gas in a dry bottle, by displacement of 
 air. Breathe across the mouth of the bottle to deter- 
 mine when it is full of the gas. Cover with a glass 
 plate and invert it in water in a pneumatic trough. 
 Kernove the plate and note what happens. Replace 
 the plate below the surface of the water, and remove 
 the bottle and contents. Test the liquid with red and 
 with blue litmus paper. Place a drop on the tongue. 
 Taste ? Connect the flask again at A with the absorp- 
 tion apparatus and continue heating till no more gas 
 is given off. Allow the flask to cool. It contains 
 crystals of acid sodium sulphate (HNaSOj. Now 
 complete the reaction : 
 
 NaCl + H 2 SO 4 = . . . 
 
 Test a little of the liquid in the first bottle, in 
 separate test-tubes, with each of the following : iron 
 filings, zinc, and manganese dioxide (warm). What 
 takes place in each case ? Reactions ? 
 
 Test the liquid with red and with blue litmus paper. 
 To a little of the same solution (first bottle) add 
 in separate tests a few cc. of the following solutions : 
 silver nitrate (AgNO 3 ), mercurous nitrate (HgNO,), 
 and lead nitrate (Pb(NO 3 ) 2 ). Write reactions noting 
 that 1 molecule of lead nitrate reacts with 2 mole- 
 cules of hydrochloric acid, while each of the other 
 nitrates reacts with 1. 
 
 Allow the lead chloride to settle and pour off 
 the liquid as completely as possible without dis- 
 turbing the solid. Add a few drops of water and 
 heat to boiling, continuing the process till solution 
 is just effected. Allow to cool. What do you observe ? 
 What do you conclude as to relative solubility of lead 
 chloride in hot and in cold water ? 
 
38 THE NON-METALLIC ELEMENTS. 
 
 Other methods of preparing hydrochloric acid : 
 (1) Treat a little ammonium chloride in a test-tube 
 with concentrated sulphuric acid and test the escaping 
 
 (2) Treat a little potassium chloride in the same 
 way. 
 
 (3) Add a little concentrated sulphuric acid to a 
 little concentrated hydrochloric acid from the bottle 
 on your desk. Is the hydrochloric acid displaced 
 from its solution (concentrated hydrochloric acid 
 means a strong solution of the gas in water) by sul- 
 phuric acid? 
 
 Beferences : Clk., pp. 118-121 ; Cly., pp. 76-80 ; E., 
 pp. 103-108; S., pp. 97-98; S. andL., pp. 68-71 ; W., 
 pp. 110-114 
 
EXERCISE 14. 
 
 CLASSIFICATION OF CEKTAIN COMPOUNDS. 
 
 For convenience many compounds (by no means all) can be classi- 
 fied as acids, bases, and salts, or as simple derivatives of these. 
 
 (a) ACIDS. Write the names and formulas of the 
 three acids that you have used'in these exercises. Find 
 the names and formulas of five other acids in your text- 
 book. What element is present in all acids ? Put a 
 drop of sulphuric acid in 25 cc. of distilled water, 
 moisten a glass rod with this diluted acid, and taste. 
 Repeat the same experiment, using nitric acid instead 
 of sulphuric acid. Test each with red and with blue 
 litmus paper. Results? (Note. Use very small pieces 
 of litmus paper, a fresh piece for each test.) Now 
 tell all you can about the characteristics of acids. 
 Does your description apply to all (as very weak or 
 insoluble) acids ? To answer this, test as above a little 
 of a stearine candle (which consists largely of stearic 
 acid). Eesults ? 
 
 (b) BASES. Try the action of each of the following 
 solutions with litmus paper : sodium hydrate, potas- 
 sium hydrate, ammonium hydrate (" ammonia "), 
 barium hydrate, and calcium hydrate (" lime-water "). 
 What do you observe ? 
 
 Put a little solid magnesium oxide on red litmus 
 paper and moisten ; allow to stand .several minutes. 
 Is the litmus changed ? Taste a drop of very dilute 
 solution of sodium hydrate ; of calcium hydrate. What 
 
40 THE NON-METALLIC ELEMENTS. 
 
 have you learned about bases ? Do these character- 
 istics apply to insoluble or very weak ba^es or basic 
 oxides ? To answer, test the action of moistened zinc 
 oxide or copper oxide on red litmus paper. 
 
 (c) SALTS. Dissolve a little pure sodium chloride in 
 distilled water in a clean test-tube and test the solu- 
 tion with litmus paper of both colors. Is either 
 affected ? Kepeat with potassium chloride; magnesium 
 sulphate; sodium sulphate; potassium nitrate. 
 
 Dissolve 2 grms. sodium hydrate in 5 cc. water in an 
 evaporating-dish by the aid of gentle heat. Add di- 
 lute hydrochloric acid 1 cc. at a time till the solution 
 is just neutral. After each addition, test in the follow- 
 ing way : A glass rod, drawn to a point, is dipped into 
 the solution ; the point is placed on blue litmus paper. 
 As soon as the acid is in excess the spot where the rod 
 touches becomes red. Stir to be sure that the solu- 
 tion is well mixed and test again. If still red, you 
 have acid in excess. Now add cautiously sodium hy- 
 drate from the reagent bottle, drop by drop, stirring 
 well and testing after each addition, till the solution 
 changes neither red nor blue litmus. If you acci- 
 dentally add a trifle too much sodium hydrate, neu- 
 tralize with a very dilute acid solution. Filter if the 
 solution is not perfectly clear and evaporate to about 
 one half the former volume. Now test again with lit- 
 mus to make sure that you made no error when you 
 decided that the solution was neutral. If not per- 
 fectly neutral, neutralize. Now place the dish on a 
 wire gauze and evaporate to dryness over the open 
 flame. What is the substance ? Eeaction by which 
 it is made ? Weigh it. If you used exactly 2 grms. 
 of sodium hydrate, how much salt ought you to get by 
 the above reaction ? 
 
CLASSIFICATION OF CERTAIN COMPOUNDS. 41 
 
 Do all salts give a neutral reaction with litmus ? 
 Test (in solution) sodium carbonate, potassium car- 
 bonate, copper sulphate, alum, and iron (ferric) chlo- 
 ride. Do weak acids perfectly neutralize the strong 
 basic properties of sodium and potassium ? Does 
 weakly basic iron counteract the acid properties of 
 chlorine in ferric chloride ? 
 
 References : Clk., p. 61 ; Cly., pp. 43-47; K, ppl 116- 
 132 ; S., pp. 75-79 ; S. and L., pp. 58-62 ; W., pp. 89- 
 96. 
 
EXERCISE 15. 
 NlTBOGEN. 
 
 Nearly pure nitrogen can be obtained from the air by burning phos- 
 phorus in a closed vessel. Phosphorus should be kept and cut under 
 water. Handle with pincers, and throw all unconsumed pieces in 
 the slop-jar. After using, heat the deflagrating-spoon to ignite any 
 pieces that may adhere to it. 
 
 Make a deflagrating-spoon with some copper wire 
 and a piece of crayon hollowed at one end. Bend in 
 the shape shown in Fig. 17. 
 
 Place a piece of phosphorus as large as a pea in the 
 cup of the spoon. Light the phosphorus, in- 
 sert in an inverted bottle, and immediately 
 immerse the mouth of the bottle about an 
 inch below the surface of the water in the 
 pneumatic trough. A little air is first driven 
 out. Why is this ? Note carefully the burn- 
 ing. The white fumes are phosphorus 
 pentoxide (P 2 O 6 ). In a short time the cloud 
 disappears. Where does it go ? Why does 
 the water rise in the bottle ? What proportion of 
 the air remains ? What has become of the oxygen ? 
 Allow the bottle to stand in the water for fifteen 
 minutes, then slip a glass plate under the bottle below 
 the surface of the water and invert the bottle and 
 its contents. 
 
 Has nitrogen any color, odor, or taste ? Will it 
 burn? Will it support combustion? Test with a 
 
 43 
 
NITROGEN. 43 
 
 glowing splinter ; also with burning sulphur. Is 
 nitrogen chemically active ? 
 
 Consult your text if necessary in answering the fol- 
 lowing questions : 
 
 What purpose does nitrogen serve in the air ? How 
 can it be shown that air is a mixture and not a com- 
 pound ? What part of the air is nitrogen, by volume 
 and by weight ? Is nitrogen lighter or heavier than 
 air ? than oxygen ? 
 
 References: Clk., pp. 49-54; Cly., pp. 115, 116, 
 124-126 ; K., pp. 126-128 ; S., pp. 50, 51, 82-85 ; 
 S. and L., pp. 10-14, 18-20 ; W., pp. 26-30, 185-189. 
 
EXERCISE 16. 
 AMMONIA. 
 
 Set up apparatus as in Exercise 13, without the 
 thistle-tube. See Figs. 15 and 16. Use an asbestos 
 plate instead of the wire gauze. Place 10 grms. of 
 quicklime (free from air-slaked lime and stone) in 
 the flask, add 10 cc. water and warm gently. Allow to 
 cool and add 15 grms. of ammonium chloride. Mix 
 by cautiously shaking. 
 
 Set up and fill the absorption apparatus exactly as 
 in Exercise 13. Now heat, and when the gas comes 
 off freely disconnect at A long enough to perform the 
 following experiments : 
 
 (a) Test the escaping gas with a glowing splinter. 
 Does it burn ? Does it support combustion ? 
 
 (6) Test it with red and with blue litmus paper. 
 Kesults ? 
 
 (c) Collect a bottle of ammonia just as you col- 
 lected hydrochloric acid, by displacement of air- 
 holding, however, the mouth of the bottle downward. 
 Let the tube reach up almost to the bottom of the 
 bottle. To tell when full, test with a piece of moist- 
 ened red litmus paper held near the mouth of the 
 bottle. Test the solubility as you did in the case of 
 hydrochloric acid. 
 
 (d) Is ammonia lighter or heavier than air? Does 
 the gas seem to diffuse upward or downward most 
 rapidly as it escapes at A? Test with litmus. 
 
 44 
 
AMMONIA. 45 
 
 Now connect the absorption apparatus and continue 
 to heat as long as gas comes off freely. Too long 
 heating is liable to crack the flask. 
 
 The first bottle should contain a strong solution of 
 ammonia in water. Since this solution acts vry much 
 like potassium hydrate, we assume that ammonium 
 hydrate has been formed according to the reaction : 
 NH S + H 3 O = NH 4 OH. 
 
 Divide the solution into two parts. Neutralize one 
 with hydrochloric acid and evaporate to dryness over 
 a low flame. "What remains ? Reaction by which it 
 was formed ? Heat a little in a dry test-tube. What 
 collects on the sides of the test-tube ? This process 
 is called sublimation. Treat a little of the sublimate 
 in a test-tube with sodium hydrate solution and warm. 
 Odor given off? 
 
 Neutralize the other half of the ammonium hydrate 
 solution with dilute sulphuric acid, Eeaction ? Evap- 
 orate and test the residue with sodium hydrate. What 
 is given off ? How did you recognize it ? Complete 
 the reaction : 2NaOH + (NH 4 ) 2 SO 4 = . . . 
 
 Note. In case your ammonium hydrate solution proves too weak 
 to give the salts in sufficient quantity, use the ammonia solution on 
 your desk for neutralization with the acids. 
 
 Has ammonia any odor or color ? Has it neutral, 
 acid, or basic properties ? Compare it with hydrogen 
 and with nitrogen. Does it resemble the elements of 
 which it is composed? What is the source of the 
 ammonia of commerce ? What are some of the uses 
 of ammonia ? 
 
 References: Clk., pp. 53-57; Cly., pp. 117, 118; 
 R., pp. 133-141 ; S., pp. 52-58; S. and L., pp. 62-67 ; 
 W., pp. 133-138. 
 
EXERCISE 17. 
 
 The apparatus 
 shown in Fig. 18. 
 
 NITRIC ACID. 
 
 used in preparing nitric acid is 
 The retort should be small (100 to 
 200 cc.). Place in the retort 15 
 grms. sodium nitrate and 10 cc. 
 concentrated sulphuric acid. Fill 
 the beaker containing the test- 
 tube nearly full of cold water. 
 Now heat the gauze gently, as 
 long as a liquid collects in the 
 test-tube used as a receiver ; then 
 remove the burner and allow the 
 retort to cool. Note the color and 
 odor of the liquid collected. Is 
 it the same compound as the con- 
 centrated nitric acid on your desk? Try the action 
 of a few drops of each (diluted with a little water) on 
 copper. Place a small piece of finger-nail in a drop 
 of the undiluted acid and note the color after washing 
 with water. The same result is produced on many 
 animal substances. 
 
 Nitric acid is colorless. The reddish-brown gas 
 seen in the retort and receiver is nitrogen dioxide. 
 The nitric acid may be colored by some of this sub- 
 stance in solution. When the retort is cool, pour in a 
 little water and heat carefully, adding more water, 
 1 cc. at a time, till the substance (NaHSO 4 ) is dis- 
 
 46 
 
 FIG. 18. 
 
NITRIC ACID. 47 
 
 solved. Filter the solution thus obtained. If you 
 have not added too much water, crystals will separate 
 out on cooling. If none appear, concentrate by evap- 
 oration (one half former volume) and cool again. When a 
 good crop of crystals is obtained, pour off the liquid, 
 redissolve the crystals in as small a quantity as possi- 
 ble of distilled water, and crystallize as before. Pour 
 off the liquid and dry crystals on filter-paper. Dis- 
 solve one or two in distilled water. Is the solution 
 acid, basic, or neutral? Label the crystals sodium 
 bisulphate and hand them to your instructor. Com- 
 plete the reaction : NaNO 3 + H a SO 4 = NaHSO 4 + . . . 
 
 Sodium bisulphate is an acid salt. Compare its 
 symbol with the symbol of sodium sulphate and of 
 sulphuric acid. 
 
 Now explain what is meant by the term " acid salt." 
 
 Action of Nitric Acid on Metals. 
 
 (a) How did you make hydrogen from sulphuric 
 acid ? From hydrochloric acid ? Can you make 
 hydrogen by the action of nitric acid on a metal ? 
 Try with zinc ; with iron. Test the escaping gas in 
 each case. Can you detect hydrogen ? Nitric acid is 
 a good oxidizing agent. It oxidizes the hydrogen to 
 water. 
 
 (&) Place a little tin in a test-tube and just cover with 
 concentrated nitric acid. Heat gently. If action does 
 not begin at once, add a few drops of water and warm 
 again. Examine the substance left. It is a compound 
 consisting mostly of tin and oxygen, the latter derived 
 from the nitric acid. 
 
 What are some of the most important salts of nitric 
 acid ? How are they obtained ? What use is made 
 of nitric acid in the manufacture of high explosives ? 
 
48 THE NON-METALLIC ELEMENTS. 
 
 PROBLEMS. 
 
 (1) How much nitric acid can be made from 150 
 grms. of sodium nitrate ? 
 
 (2) From the same quantity of potassium nitrate ? 
 
 (3) 300 grms. nitric acid are required; how much 
 sodium nitrate must be used? 
 
 (4) How much sodium bisulphate will be formed in 
 Problem 3? 
 
 References : Clk., pp. 58-60 ; Cly., pp. 119, 120 ; K., 
 pp. 143-148 ; S., pp. 67-70 ; S. and L., pp. 55-57 ; 
 W., pp. 116-122. 
 
EXERCISE 18. 
 
 COMPOUNDS OF OXYGEN AND NITROGEN. 
 
 (a) Nitrous Oxide (N,0). 
 
 Set up apparatus as shown in Fig. 11. Heat in the 
 test-tube 5 grms. of ammonium nitrate till it seems to 
 boil. Drive off the gas at as low a temperature as 
 possible and collect in bottles by displacement of 
 water. Allow the bottles to stand in water for fifteen 
 minutes before examining ; 
 then test color, odor, and 
 taste. Will the gas burn? 
 Will it support combus- 
 tion? Is it soluble in 
 water to any marked ex- 
 tent? 
 
 Complete the reaction 
 NH 4 NO, (heated) = . . . 
 
 (b) Nitric Oxide (NO). 
 
 Use apparatus shown 
 in Fig. 19. Put 15 grms. 
 of copper in the flask and 
 add dilute nitric acid 
 through the thistle-tube. 
 Collect the gas by displacement of water. Add the 
 acid a little at a time so that the gas may come off 
 gradually. Warm a little now and then, regulating 
 
 49 
 
 FIG. 19. 
 
50 THE NON-METALLIC ELEMENTS. 
 
 the supply of acid and tlie temperature so as to 
 produce a regular evolution of gas. If the gas begins 
 to come off too rapidly, pour in cold water through 
 the thistle-tube. 
 
 Eeaction : 3Cu+8HNO 1 = 3Cu(NO,) 1 +4H 1 O+2NO. 
 
 Test the properties of nitric oxide. Will it burn ? 
 Will it support combustion? 
 
 (c) Nitrogen Peroxide 
 
 Turn upwards one of the bottles containing the 
 colorless nitric oxide just obtained and uncover. The 
 gas absorbs oxygen from the air and becomes the 
 reddish-brown nitrogen peroxide. Write the reaction. 
 Does nitrogen peroxide burn ? Does it support com- 
 bustion ? Is it soluble in water ? Add a little water 
 to a bottle of the gas, cover with the hand, and shake 
 well. Does the color disappear? Now explain the 
 colored appearance of the gas in the flask used in 
 preparing nitric oxide, and the fact that a colorless 
 gas was collected by displacement of water. 
 
 Which of the compounds studied in this exercise 
 most resembles oxygen? How can you explain the 
 fact that the one that contains the smallest per cent 
 of oxygen is the only one that you found to be a 
 supporter of combustion ? 
 
 (e) The Law of Multiple Proportions 
 is well illustrated by the compounds studied in (a), 
 (b), and (c). We will assume that nothing is known 
 about atoms, molecules, and symbols. All that we 
 need to know is that we have three distinct com- 
 pounds (not mixtures), each composed of oxygen and 
 nitrogen. It can be shown that heated copper has 
 the property of absorbing all the oxygen in any of 
 
COMPOUNDS OF OXYGEN AND NITROGEN. 51 
 
 them, leaving behind all the nitrogen. If we make 
 such an analysis in each case we shall obtain the fol- 
 lowing results : 
 in 11 grms. nitrous ) 7 grms. nitrogen, 4 grins. 
 
 oxide, ) oxygen, 
 
 in 15 grms. nitric ) 7 grms. nitrogen, 8 grms. 
 
 oxide, ) oxygen, 
 
 in 23 grms. nitrogen | 7 grms. nitrogen, 16 grms. 
 
 peroxide, j oxygen. 
 
 How can the simple ratio 4 : 8 : 16 (1 : 2 : 4) be ex- 
 plained? Answer: By assuming that compounds are 
 made up of simple units or atoms. Hence the simple 
 ratio of weights is to be explained by assuming a 
 simple ratio in the numbers of the atoms in the 
 compounds. 
 
 That the weight relations just considered are in 
 harmony with the molecular weights as derived from 
 the symbols given in the exercise can be readily seen 
 from the following : 
 
 nitrous oxide, 7 : 4 = 14 + 14 : 16 . . . N 2 O. 
 nitric oxide, 7:8= 14 : 16 ... NO. 
 
 nitrogen peroxide, 7 : 16 = 14 : 16 + 16 . NO a . 
 
 State the law of multiple proportions. 
 
EXERCISE 19. 
 
 CARBON. 
 
 Heat in a porcelain or metal crucible one piece 
 each of hard and of soft wood covered with sand. 
 Light the gas above the sand. Does the charcoal 
 from the different woods differ in physical properties ? 
 Put a little powdered charcoal on platinum foil and 
 heat strongly. Does it burn ? Try the same experi- 
 ment with graphite (another form of carbon) from 
 your pencil. Is carbon active at ordinary tempera- 
 tures? Is it attacked by acids or alkalies? Try 
 with those on your desk. Carbon in the form of 
 " lamp-black " is used in preparing printer's ink. 
 Why is printer's ink as well as India ink so perma- 
 nent? 
 
 Name and describe three allotropic forms of carbon. 
 
 (a) Charcoal as an Absorbent. 
 
 To a test-tube one third full of water add indigo solu- 
 tion till the water is distinctly blue. Now add 1 grm. of 
 animal charcoal and heat, constantly shaking for sev- 
 eral minutes. Filter, and note whether the blue color 
 has disappeared. 
 
 Kepeat the experiment, using litmus solution instead 
 of indigo. Results? 
 
 Dilute hydrogen sulphide water till the odor is 
 only just distinctly noticeable. Shake with animal 
 charcoal and note odor before and after shaking. 
 
 53 
 
CARBON. 53 
 
 Eesults ? What do you conclude from these experi- 
 ments concerning the absorbent power of carbon in 
 the form of animal charcoal? 
 
 (b) Carbon as a deducing Agent. 
 
 (1) Mix by grinding in a mortar 3 grms. of powdered 
 copper oxide with 0.2 grm. of wood charcoal. Put in 
 a small porcelain crucible and cover 
 
 with a very thin layer of pulverized 
 charcoal, then place the crucible cover 
 on the crucible to protect the mixture 
 from the action of the air. Place the 
 crucible and its contents on a wire or 
 pipe triangle, and heat strongly for 
 five minutes with Bunsen or gasoline 
 burner. See Fig. 20. (Few alcohol- 
 lamps give sufficient heat for this reac- ^ FIG 
 tion.) Cool and examine the contents 
 of crucible. Has the copper oxide been reduced to 
 copper ? 
 
 Try the action of some of the reddish substance 
 with nitric acid. Complete the reaction 
 
 2CuO + C = CO, + . . . 
 
 (2) Heat a little lead oxide (PbO) on charcoal before 
 the blowpipe. (The use of the blowpipe is fully 
 described in most works on chemistry. See index in 
 text or reference-books.) Is the lead oxide reduced 
 by the heated charcoal? Complete the reaction 
 2PbO + C = . . . 
 
 (c) Test for Carbon. 
 
 Carbon is most readily detected by burning it to 
 carbon dioxide. Make several bottles of oxygen as 
 
54 TEE NON-METALLIC ELEMENTS. 
 
 in Exercise 6. Cover with greased glass plates and 
 reserve for the following experiments : 
 
 (1) Fasten a piece of charcoal to a piece of wire, 
 heat to glowing, and burn in a bottle of oxygen. As 
 soon as the charcoal ceases to glow, add 5 cc. of clear 
 lime-water and shake. What do you notice ? 
 
 Keaction : Ca(OH) 2 + CO, = CaCO 3 + H,O. 
 CaCO 3 is insoluble in water, hence the liquid 
 becomes turbid. 
 
 (2) Kepeat the experiment, using a piece of candle 
 instead of charcoal. Does the candle contain carbon ? 
 Why do you think so? How would it be possible to 
 prove that the diamond is carbon ? 
 
 References: Clk., pp. 74-79; Cly., pp. 147-152; R, 
 pp. 156-167 ; S., pp. 125-131 ; S. and L., pp. 166-176 ; 
 W., pp. 44-52. 
 
EXERCISE 20. 
 
 COMPOUNDS OF CARBON AND OXYGEN. 
 
 (a) Carbon Dioxide. 
 
 Set up apparatus consisting of a large test-tube 
 carrying a thistle-tube and a delivery-tube. See 
 Fig. 21. Put a little solid sodium car- 
 bonate into the test-tube and add dilute 
 hydrochloric acid through the thistle- 
 tube. Pass the escaping gas into lime- 
 water. 
 
 Now try in separate tests the action of 
 sodium carbonate with dilute sulphuric, 
 nitric, and acetic acids. Does a gas 
 escape which renders lime water turbid in FIG. 21. 
 each case ? 
 
 Try the action of marble (calcium carbonate) with 
 each of the acids mentioned above. Is the same gas 
 liberated as before ? 
 
 Complete the reactions : 
 
 Na t CO, + 2HC1 = H a O + . . . 
 Na,CO s + H 2 S0 4 = H 2 + . . . 
 Na 2 CO, + 2HNO, = H a O + . . 
 
 Note that calcium replaces two atoms of hydrogen 
 and complete the following : 
 
 CaC0 3 + 2HC1 
 CaCO, + H 2 SO 4 = . . . 
 
 CaCO, + 2HN0 3 
 
 55 
 
56 THE NON-METALLIC ELEMENTS. 
 
 Prepare carbon dioxide for study by the action of 
 hydrochloric acid on marble. Use apparatus shown 
 in Fig. 15, and collect the gas by displacement of air. 
 Will the gas burn or support combustion ? Test with 
 a lighted splinter. Is it lighter or heavier than air? 
 Pour it as you would water on a lighted splinter. 
 Kesult ? Pour the gas in one bottle into another, and 
 test for carbon dioxide in the second bottle with a 
 burning splinter. Is carbon dioxide soluble in water ? 
 Test as follows : Collect a bottle of the gas by dis- 
 placement of air. Now remove deli very- tube and 
 insert a thistle-tube through the hole in the paste- 
 board cover. Fill the bottle one third full of cold 
 water through the thistle-tube. Remove tube and 
 cover, close tightly with the hand and shake vigor- 
 ously for a minute or two. After putting the mouth 
 of the bottle under water, remove the hand and note 
 result. 
 
 Dissolve 2 grms. of solid sodium hydrate in 10 cc. 
 distilled water and allow to cool. Place in a test- 
 tube and pass in carbon dioxide rapidly. Does the 
 solution become warm? After the gas is no longer 
 absorbed test the solution with acids. Does it behave 
 like a solution of sodium carbonate ? 
 
 Complete the reaction : 
 
 2NaOH + CO, = . . . 
 
 Why do you get a precipitate with calcium hydrate 
 and not with sodium hydrate ? Compare the solubil- 
 ity of the two carbonates. 
 
 Pass your breath through a solution of calcium 
 hydrate in a test-tube. What does this show ? Allow 
 a little of the hydrate solution to stand exposed to the 
 
COMPOUNDS OF CARBON AND OXYGEN. 57 
 
 air for several hours. What evidence have you that 
 the air contains carbon dioxide ? 
 
 What use is made of carbon dioxide by growing 
 plants ? (See text.) 
 
 (b) Carbon Monoxide. 
 
 Connect to the apparatus used in generating car- 
 bon dioxide (Fig. 15) a wash-bottle such as you 
 used in purifying hydrogen (Fig. 14). Put into the 
 flask 10 grms. oxalic acid, and add 30 cc. concen- 
 trated sulphuric acid through the thistle-tube. Fill 
 the wash-bottle half full of sodium hydrate solu- 
 tion. Now heat gently at first, afterwards more 
 strongly, and, when air is expelled, collect gas by 
 displacement of water. 
 
 Keaction : C 2 H 2 O 4 = CO a + CO + H 2 O. 
 
 The sulphuric acid serves to remove water from the 
 oxalic acid. Why is the wash-bottle containing 
 sodium hydrate used? 
 
 Give physical properties of carbon monoxide. 
 Compare it in all respects with carbon dioxide. Ex- 
 plain how the two oxides of carbon illustrate the law 
 of multiple proportions. 
 
 References : Clk., pp. 90-98 ; Cly., pp. 153-156 ; E., 
 pp. 168-179 ; S., pp. 136-145 ; S. and L., pp. 176-183 ; 
 W., pp. 165-178. 
 
EXERCISE 21. 
 
 FLAMES. 
 (a) The Nature of Flames. 
 
 Heat a piece of charcoal till it glows. Here is 
 combustion, but no flame. Did you get a flame 
 when glowing charcoal was plunged into oxygen, 
 or only a more intense glowing ? Now light a candle. 
 Have you here a flame ? After it is burning well, 
 blow it out suddenly, and hold a lighted splinter 
 a little above the wick. Can you relight the candle 
 without applying the light to the wick ? 
 
 Place 1 grm. of stearin (from a candle) in a small 
 crucible. (See Fig. 20.) Heat strongly. Are gases 
 evolved ? Can you light them above the crucible ? 
 
 Repeat the experiment, using a few drops of alcohol. 
 Results? Fill a test-tube one-third full of bits of 
 wood and heat. Are combustible gases given off? 
 Do you think that any substance that burns with a 
 flame will, on heating, give off combustible gases ? 
 If so, what is a flame? 
 
 (b) Kindling-point. 
 
 Do all substances begin to burn at the same tem- 
 perature ? Test with the following : 1 cc. of carbon 
 d!sulphide, in a small beaker ; a match ; and a candle. 
 Warm a glass rod and hold in the vapor of the carbon 
 disulphide, then immediately touch each of the other 
 
 58 
 
FLAMES. 59 
 
 two. Repeat the experiment with the rod a little 
 hotter each time, till one of the substances is kindled. 
 Now see which of the remaining two you can light 
 with a hot rod. Does each substance seem to have 
 its own distinct kindling-point ? 
 
 Bring down a piece of wire gauze on the flame of a 
 burner. Does the flame pass through the gauze ? 
 Apply a light above the gauze. What takes place ? 
 Explain fully the principle of the safety-lamp. 
 
 (c) Light of Flames. 
 
 Could you read well by the light of an alcohol or a 
 hydrogen-flame ? Hold a clean evaporating-dish in 
 burning alcohol. Is any soot (carbon) deposited? 
 Try the same experiment with a candle-flame. To 
 what is the light of an ordinary flame principally due ? 
 
 Alcohol is a little over 50$ carbon. Oil of turpen- 
 tine is nearly 90$ carbon. Which do you think will 
 burn with the more luminous (and sooty) flame? 
 Light a very little of each, and see if your reasoning 
 is correct. 
 
 References : Clk., pp. 84-89 ; Cly., pp. 159-171 ; R, 
 pp. 180-189 ; S., pp. 27-29 ; S. and L., pp. 183-193; 
 W., pp. 53-62. 
 
EXERCISE 22. 
 
 BROMINE. 
 
 Work with bromine must be performed under the hood or where 
 the draft is good. Avoid inhaling the fumes. 
 
 (a) Bromine-vapor. 
 
 Place in a large test-tube 2 or 3 crystals of potassium 
 bromide with an equal quantity of manganese dioxide. 
 Add a few drops of concentrated sulphuric acid and 
 warm. Note color of vapor. Will it bleach? Try 
 with moistened calico. How does the action compare 
 with that of chlorine? 
 
 (b) Bromine (Liquid) and Bromine-water. 
 
 Put a pulverized mixture consisting of 3 grms. po- 
 tassium bromide and an equal weight of manganese 
 dioxide into retort of apparatus shown in Fig. 18. 
 Pour 10 cc. concentrated sulphuric acid into 50 cc. 
 of water, and when the liquid is cool introduce it by 
 means of a funnel into the retort. Shake to be sure 
 that the acid is in contact with all parts of the mixture 
 and then heat gently. Put a little water into the test- 
 tube used as a receiver, and let the end of the retort 
 dip below the surface of the water. This is to prevent 
 evaporation. Now continue to heat till brown fumes 
 no longer come off. 
 
 . The heavy brown liquid in the test-tube is bromine. 
 Compare it with chlorine, giving the physical proper- 
 ties of each. The reaction representing the liberation 
 
 6u 
 
BROMINE. 61 
 
 of bromine is exactly analogous to the reaction that 
 you learned in preparing chlorine. Write the reaction 
 for bromine. 
 
 How do you account for the color of the water above 
 the bromine? Is bromine soluble in water? 
 
 Bromine is very soluble in carbon disulphide. To 
 a few cc. of bromine-water (free from liquid bromine) 
 in a test-tube add 1 drop of carbon disulphide, close the 
 test-tube with the thumb and shake vigorously. Allow 
 to settle. Which now contains the bromine in solu- 
 tion, the water or the carbon disulphide ? Note the 
 color of each. Do you think that you could prove the 
 presence of bromine in solution by this test? Now 
 try the same test with a solution of potassium bro- 
 mide. Can we use this test for compounds containing 
 bromine or only for bromine itself (free bromine)? 
 
 To a few cc. of a dilute solution of potassium 
 bromide add a little chlorine-water. Does the solu- 
 tion become colored ? Now shake with a drop of car- 
 bon disulphide. Has bromine been liberated by the 
 chlorine? Which has the greater affinity for potas- 
 sium, bromine or chlorine ? Complete the reaction : 
 KBr + Cl = . . . 
 
 (c) Hydrobromic Acid and some of its Salts. 
 
 Put a crystal of potassium bromide in a test-tube, 
 add a little dilute sulphuric acid and heat. Test the 
 escaping gas with litmus paper. Write the reaction 
 representing the liberation of hydrobromic acid. See 
 corresponding reaction for hydrochloric acid. 
 
 In making the following bromides we may use either 
 hydrobromic acid or a soluble bromide. 
 
 AgNO, + HBr = AgBr + HNO S . 
 AgNO, + KBr = AgBr -} KNO,. 
 
62 THE NON-METALLIC ELEMENTS. 
 
 Add a few drops of potassium bromide solution, in 
 separate tests, to solutions of silver nitrate, mercurous 
 nitrate, and lead acetate. Describe results and write 
 reactions. 
 
 (d) PROBLEMS. 
 
 1. How much bromine can be obtained from 60 
 grms. potassium bromide ? 
 
 2. How much potassium bromide must be taken to 
 obtain 60 grms. of bromine ? 
 
 3. How much potassium bisulphate will be formed 
 in problem 2 ? 
 
 References: Clk., p. 128; Cly., p. 75; K., pp. 217- 
 220; S., pp. 108-114; S. and L., pp. 87-90; W., pp. 
 208-211. 
 
EXERCISE 23. 
 
 IODINE. 
 
 Grind together in a mortar 2 grms. of potassium 
 iodide and 4 grms. of manganese dioxide. Place the 
 mixture in a beaker of 300 to 400 cc. capacity and add 
 drop by drop about 5 cc. of concentrated sulphuric 
 acid. Select an evaporating-dish whose diameter is 
 a little larger than that of the beaker. Fill the 
 evaporating-dish three fourths full of water, see that 
 the under surface is perfectly clean and dry, and place 
 on the beaker. Now set beaker and contents, covered 
 as just directed, on a wire gauze supported by the 
 ring-stand. Heat cautiously and note the color of 
 the iodine-vapor. Conduct the heating in such a way 
 that the iodine-vapor just fills the beaker. (Too rapid 
 heating is to be avoided. Half an hour will be re- 
 quired to obtain good results.) If the iodine collects 
 on the sides of the beaker, vaporize . it by cautious 
 heating. Continue the heating till nearly all the 
 iodine has collected on the cool surface of the evapora- 
 ting-dish. Then remove the dish, throw out the water 
 without wetting the iodine, and scrape the iodine off 
 the dish. Now refill the dish with cool water, and 
 see if you can sublime any more iodine against it. If 
 so, add it to the portion first obtained. 
 
 The liberation of iodine is analogous to the libera- 
 tion of chlorine or bromine. Write the reaction for 
 
 63 
 
64: THE NON-METALLIC ELEMENTS. 
 
 iodine. Describe in detail everything that you have 
 noticed in connection with the preparation of iodine. 
 
 The most delicate test for iodine is a solution of 
 starch paste. Prepare this as follows: To 1 grm. 
 starch add 10 cc. water, mix well and pour into 200 cc. 
 boiling water. Stir well. Allow to cool and settle, 
 and pour off the clear liquid for use when required. 
 When the solution is cooling test the solubility of 
 iodine in the following liquids : water, alcohol, carbon 
 disulphide, and a solution of potassium iodide. Use 
 a test-tube full half of (hot) water and 4 or 5 drops of 
 each of the other solvents. In which do you think 
 that iodine is the most soluble ? 
 
 Now make the " starch test " as follows : Add a few 
 cc. of the starch solution to 100 cc. of water and then 
 add the water solution of iodine till a deep blue ap- 
 pears. If you do not succeed in this way, dilute the 
 solution of iodine in potassium iodide with a large 
 excess of water and add a drop of this dilute solution. 
 The success of the experiment depends on the relative 
 amounts of starch, water, and iodine. 
 
 To another portion of the water solution or to a very 
 dilute potassium iodide solution of iodine add a drop 
 of carbon disulphide and shake well. What takes 
 place ? Compare the deportment of bromine with this 
 reagent. 
 
 Dissolve a minute amount of potassium iodide in a 
 test-tube half full of water. Does the solution react 
 with starch ? Now add a drop or two of chlorine-water 
 and note result. Shake a little of potassium iodide 
 solution with a drop of carbon disulphide. Does any 
 change of color occur ? Now add a drop or two of 
 chlorine-water and shake again. Result? Explain 
 fully the principles involved. 
 
IODINE. 65 
 
 Treat silver nitrate, mercurous nitrate, and 
 nitrate with a solution of potassium iodide. Describe 
 results and write reactions. Compare with the action 
 of potassium bromide. 
 
 PKOBLEMS. 
 
 (1) How much potassium iodide must you take to 
 obtain 100 grms. of iodine ? 
 
 (2) How much manganese dioxide would be required 
 in problem (1) ? 
 
 References: Clk., pp. 129-131; Cly., p. 75; R, pp. 
 220-222; S. f pp. 115-118; S. and L., pp. 90-93; W., 
 pp. 211-215. 
 
EXERCISE 24. 
 FLUORINE. 
 
 Give a brief description of the properties of fluorine 
 using your text-book or lecture-notes as your source 
 of information. Why do we not prepare fluorine for 
 study in the laboratory ? 
 
 Hydrofluoric Acid. 
 
 This compound attacks glass, hence we cannot well 
 study it very fully. It is liberated from its salts by 
 the action of sulphuric acid. Write the reaction that 
 takes place between calcium fluoride (CaF 2 ) and sul- 
 phuric acid. The action of hydrofluoric acid on glass 
 may be shown in the following way : Cover a piece of 
 window-glass with a coating of beeswax or paraffine 
 somewhat thicker than the paper of this book. This 
 is best done by carefully warming the glass and rub- 
 bing the wax over its surface. The coating should be 
 on both sides of the glass and as uniform as possible. 
 Engrave some design in the wax by means of a pointed 
 instrument. Be sure that the point of the instrument 
 entirely removes the wax and that the lines are not too 
 fine. Put 3 grms. calcium fluoride in a leaden dish 
 and add enough cone, sulphuric acid to form a thin 
 paste. Cover the dish with the plate that you have 
 prepared with the engraved side down. Avoid inhal- 
 ing the fumes. Allow the dish thus covered to stand 
 for several hours, or till your next laboratory period, 
 
 66 
 
FLUORINE. 67 
 
 under the hood. Next remove the plate and at once 
 wash the contents of the dish into the waste-jar. It is 
 sometimes troublesome to remove the wax. This can 
 be done without cracking the glass by putting in water, 
 heating to boiling, continuing the boiling for a few 
 minutes, then cooling till the hand can be placed in 
 the water without scalding. The plate may now be 
 removed and rubbed with a cloth moistened with alco- 
 hol. Show the etched plate to your instructor for 
 approval. The reaction between the acid and the 
 glass is as follows : 
 
 SiO 2 + 4HF = SiF 4 + 2H 2 O. 
 
 We have, for convenience, studied the halogens 
 (fluorine, chlorine, bromine and iodine) in an illogical 
 order. Now make a thorough review of these com- 
 pounds. Show in what respects they resemble each 
 other. Make a list of their atomic weights and show 
 that their properties are related to their atomic 
 weights. 
 
 References: Clk., pp. 111-113; Cly., pp. 75, 76 ; K, 
 pp. 223-225 ; S., pp. 122-124 ; S. and L., pp. 77-79, 
 94-95 ; W., p. 215. 
 
EXERCISE 25. 
 
 SULPHUR. 
 
 (a) Rhombic Sulphur. 
 
 Dissolve in a small beaker 1 grm. of roll sulphur in 
 carbon disulphide, using as small a quantity as will 
 effect solution. Set the beaker under the hood, away 
 from flames, and allow the solvent to evaporate. Note 
 the form of the crystals. 
 
 (b) Monodinic Sulphur. 
 
 Fill a porcelain crucible with roll sulphur and melt 
 at a low temperature. Add more sulphur as it melts 
 down, continuing the heating at a low temperature, till 
 the crucible is full of the molten sulphur. Now allow 
 to cool until a crystalline crust begins to form on the 
 surface. Make an opening and pour out the remain- 
 ing molten sulphur. Note the kinds of crystals in the 
 cavity. Allow them to stand several days. Do you 
 notice any change in general appearance or form ? 
 
 (Write out a brief description of each of the six 
 systems of crystals. See text or reference-books.) 
 
 (c) Plastic Sulphur. 
 
 Put about 5 grms. sulphur in a dry test-tube, held 
 with a clamp, and heat gradually. Note that you first 
 obtain a thin amber-colored liquid which gradually 
 becomes dark and viscous as the temperature rises. 
 
SULPHUR. 69 
 
 Tliis soon becomes tliinuer, and finally the tube is 
 filled with sulphur-vapor. Pour the molten sulphur 
 into a beaker containing water. Examine and describe 
 the sulphur in the beaker. Allow it to stand till your 
 next laboratory period. Is it still plastic ? 
 
 Now compare the three allotropic forms of sulphur. 
 Which form is the most stable? What substance 
 have you studied all of whose allotropic forms are 
 stable ? 
 
 Where is the greater part of the sulphur of com- 
 merce obtained ? How is it freed from impurities ? 
 
 References : Clk., pp. 132-137 ; Cly., pp. 101-103 ; 
 E M pp. 226-230 ; S , pp. 157-160 ; S. and L., pp. 99- 
 105 ; W., pp. 238-243, 108. 
 
EXERCISE 26. 
 
 SULPHIDES. 
 (a) Hydrogen Sulphide. 
 
 All work with hydrogen sulphide must be done under the hood or 
 where the draft is good. Put all residues in waste-jar under the 
 hood or out of doors. Avoid inhaling the gas. 
 
 Set up apparatus exactly as in Fig. 13, except the 
 delivery-tube. Put 20 grms. ferrous sulpliide in the 
 generator and 50 cc. of water in the small bottle. 
 Attach to this bottle a delivery-tube such as you have 
 used in collecting gases by displacement of air. 
 When the apparatus is in order, pour dilute sulphuric 
 acid into the generator through the thistle-tube. After 
 all air is expelled, collect a bottle of the washed gas 
 by displacement of air. (Hydrogen sulphide is a 
 little heavier than air.) Will it burn ? W T ill it sup- 
 port combustion ? Has it any color or odor ? Test 
 its solubility in the water in the following way : Pass 
 a few bubbles of the gas into water in a test-tube. Is 
 the gas entirely absorbed ? Is enough absorbed to 
 impart its odor to the water? Complete the reac- 
 tion showing the formation of hydrogen sulphide : 
 
 FeS + H 3 S0 4 
 
 (b) Formation of Sulphides by Direct Combination. 
 
 Pass hydrogen sulphide into a solution of copper 
 sulphate (CuSO 4 ). Write the reaction. Filter off 
 
 70 
 
SULPHIDES. 71 
 
 the precipitated copper sulphide. See note on filtra- 
 tion, Exercise 9. Wash the precipitate by filling the 
 cone formed by the filter-paper full of distilled water. 
 The water, as it soaks through, dissolves out foreign 
 matter held by the precipitate, thus "washing " it. 
 Wash thoroughly. Is the precipitate soluble in 
 dilute sulphuric acid ? If it were, could it be formed 
 by the reaction that you have written ? 
 
 Using a solution of lead nitrate, precipitate lead 
 sulphide. Filter and wash the precipitate. Test its 
 solubility in dilute nitric acid. 
 
 Pass hydrogen sulphide into a solution of ferrous 
 (iron) sulphate. Do you notice any precipitate or, 
 at most, anything more than a slight precipitate ? 
 Now add ammonium hydrate and continue to pass in 
 the gas. Filter and wash the precipitate. Reaction : 
 
 FeS0 4 + H 2 S + 2NH 4 OH = FeS + (NH 4 ) 2 SO 4 + 2H 2 O. 
 
 Test the solubility of the washed precipitate in dilute 
 sulphuric acid. What odor is given off ? Reaction ? 
 Why is ferrous sulphide not precipitated without 
 the ammonium hydrate according to the reaction : 
 FeS0 4 + H 2 S = FeS + H 2 S0 4 ? 
 
 Make a little ferrous sulphide as in Exercise 4, 
 paragraph (/). Test it with dilute sulphuric acid. Is 
 it the same substance that you have just studied? 
 Why do you think so ? 
 
 (c) Test for Soluble Sulphides. 
 
 Put a little sodium sulphide on a clean silver coin. 
 Moisten with a drop of water and crush the sulphide. 
 Allow to stand for some time and then wash. Note 
 the black spot (silver sulphide) on the coin. Since 
 sulphur or any of its compounds may be converted 
 
72 THE NON-METALLIC ELEMENTS. 
 
 into sodium sulphide by fusing with sodium car- 
 bonate on charcoal, the above test is used to detect 
 sulphur in any of its forms. Fuse a little sulphur 
 mixed with an equal quantity of sodium carbonate 
 on charcoal. Cut out the fused mass and test on 
 silver as above. 
 
 (d) Test for Hydrogen Sulphide. 
 
 Moisten a piece of filter-paper with a drop of lead 
 acetate solution. Hydrogen sulphide turns the paper 
 black. Explain. 
 
 Has hydrogen sulphide acid, neutral, or basic 
 properties ? 
 
 References: Clk., pp. 136, 137; Cly., pp. 104,105; 
 K., pp. 231-234 ; S., pp. 160-163 ; S. and L., pp. 106- 
 109 ; W., pp. 243-246. 
 
EXERCISE 27. 
 
 SULPHUR COMPOUNDS CONTAINING OXYGEN. 
 
 (a) Sulphur Dioxide. 
 
 Burn a little sulphur (deflagrating-spoon) in a wide- 
 mouthed bottle. Cautiously note the odor. Write 
 the reaction. Add a little water to the bottle and 
 shake well. Test the liquid with litmus paper. 
 
 Set up apparatus as shown in Fig. 15. Put 10 grms. 
 of copper-foil or copper turnings in the flask and add 
 about 25 cc. concentrated sulphuric acid through the 
 thistle-tube. Heat gradually, increasing the tempera- 
 ture, till a gas comes off, then moderate the heating. 
 Catch a bottle of the gas by displacement of air. Is 
 it the same compound as you prepared by burning 
 sulphur ? Test the bleaching action of sulphur 
 dioxide on a piece of red calico on a red flower, if you 
 can procure one. Compare with the action of chlorine. 
 Which bleaches the more vigorously ? 
 
 Dissolve 1 grm. of sodium hydrate in 10 cc. of dis- 
 tilled water, and pass sulphur dioxide into the solution 
 till the reaction is neutral to litmus. You now have a 
 solution of sodium sulphite, Na a SO 8 . Write the reac- 
 tion. To a small portion of the solution add HC1. 
 What gas is given off? Write the reaction. 
 
 To another portion add barium chloride solution. 
 Barium sulphite (BaSO 3 ) is formed'. Eeaction? Is 
 barium sulphite soluble in dilute hydrochloric acid ? 
 (A little insoluble barium sulphate may be present.) 
 
 73 
 
74 THE NON-METALLIC ELEMENTS. 
 
 To another portion of the sodium sulphite solution 
 add nitric acid and boil. Now add barium chloride 
 solution and treat as above. Is the precipitate solu- 
 ble in hydrochloric acid ? 
 
 Nitric acid is a good oxidizing agent. You now have 
 barium sulphate, which is insoluble in acids. 
 
 (b) Sulphuric Acid. 
 
 Describe the process of making sulphuric acid. 
 Give some of the uses of this acid. 
 
 To 1 cc. water in a test-tube add 1 cc. concentrated 
 sulphuric acid and note any change in temperature. 
 Write with this acid on a piece of paper by means of 
 a splinter. Warm for a few minutes and note result. 
 
 Put grm. sugar in a test-tube, add concentrated 
 sulphuric acid and warm. What do you notice ? 
 What do you conclude from these experiments con- 
 cerning the affinity of sulphuric acid for water ? 
 
 To a drop of dilute sulphuric acid add a little 
 barium chloride solution. Reaction ? Try to dissolve 
 the precipitate in water. In dilute acids. Results? 
 Try the same experiments, using calcium chloride 
 instead of barium chloride. 
 
 References: Clk., pp. 138-149; Cly., pp. 106-111; 
 E., pp. 235-241 ; S., pp. 164-176 ; S. and L., pp. 110- 
 120 ; W., pp. 124-132, 247, 248. 
 
EXERCISE 28. 
 
 PHOSPHORUS. 
 
 For precautions in using phosphorus see Exercise 15. 
 (a) Ydlow Phosphorus. 
 
 Put some water in an evaporating-dish and ask your 
 instructor to place in it three pieces of phosphorus 
 about the size of grains of wheat. Remove one with 
 the pincers, dry by bringing in contact with filter-paper, 
 and place in a clean dry pprcelain crucible. Note 
 that white fumes are given off. The phosphorus glows 
 in the dark. What does the word phosphorus signify ? 
 Let the crucible containing the phosphorus float on 
 water in a beaker. Place the beaker on the wire gauze 
 and heat gently. Does the phosphorus melt? Does 
 it burn ? Note the temperature of the water with 
 your hand. The white fumes are phosphorus pentox- 
 ide (P 2 O 6 ). Write the reaction representing the burn- 
 ing of phosphorus. 
 
 Perform the following experiment exactly as di- 
 rected. In a dry test-tube held with a clamp, place 1 
 cc. carbon disulphide. (Cork and remove from your 
 working place any carbon disulphide that you may 
 have aside from the amount just given.) Drop into 
 the tube one piece of phosphorus. Does it dissolve in 
 the carbon disulphide ? Cover a beaker with a round 
 filter a little larger in diameter than the beaker. 
 Now, holding the tube with the clamp, pour the solu- 
 
 75 
 
76 TEE NON-METALLIC ELEMENTS. 
 
 tion on the filter-paper. Stand a few feet distant and 
 note what takes place after the carbon disulphide has 
 evaporated. 
 
 Put a few crystals of iodine in a dry test-tube and 
 drop on them a piece of dry phosphorus. The phos- 
 phorus unites with the iodine forming PI 2 . Write the 
 reaction. 
 
 What do you conclude from these experiments about 
 the chemical activity of yellow phosphorus ? Explain 
 the use of phosphorus in matches. 
 
 (b) Red Phosphorus. 
 
 (This kind of phosphorus may be safely handled 
 without special precautions.) Is red phosphorus 
 soluble in carbon disulphide ? Does it ignite at a low 
 temperature ? Try its action on iodine. 
 
 Put i grm. of red phosphorus on the iron base of 
 your ring-stand. Ignite under the hood. Do you 
 think that the product of combustion is the same as 
 when yellow phosphorus burns ? Why ? Compare 
 the allotropic forms of phosphorus. 
 
 (c) Phosphine. 
 
 Heat a little calcium hypophosphite in a test-tube. 
 Note the inflammability of the impure phosphine (PH 9 ) 
 formed. 
 
 Complete the reaction : 2PH 8 -f- 4O a = . . . 
 
 (d) Phosphoric Acid. 
 
 Note. The acids containing phosphorus are very numerous. We 
 will here study only the orthophosphoric acid. Commercial phos- 
 phoric acid usually consists of metaphosphoric acid. This as well as 
 pyrophosphoric acid, which is sometimes present, is converted into 
 the ortho acid by boiling for some time with excess of water. 
 
PHOSPHORUS. 77 
 
 Neutralize a few cc. of a solution of orthophosplioric 
 acid with ammonium hydrate. Be sure that the solu- 
 tion is exactly neutral to litmus. Add silver nitrate 
 solution, describe the precipitate and write the reac- 
 tion. 
 
 To 1 cc. of phosphoric acid solution add a few drops 
 of a solution of ammonium molybdate. In very dilute 
 solutions the precipitate appears after some time has 
 elapsed. Describe the precipitate. 
 
 Repeat the experiment just given, using disodium 
 phosphate instead of phosphoric acid. Result ? 
 
 Test for phosphates in bone ash as follows : Digest 
 1 grm. of bone-ash with dilute sulphuric acid by gently 
 heating (not boiling) for about 10 minutes. Filter and 
 add ammonium molybdate solution to the clear filtrate. 
 Do you obtain a precipitate ? If so, describe it. 
 
 Try the same experiment, using coal-ash instead of 
 bone-ash. Have you any evidence that coal-ash con- 
 tains phosphates ? 
 
 What use is made of the natural phosphates? 
 
 References : Clk., pp. 151-158 ; Cly., pp. 130-133 ; 
 E, pp. 241-248 ; S., pp. 193-196 ; S. and L., pp. 139-147 ; 
 W., pp. 249-258. 
 
EXERCISE 29 
 
 ARSENIC. 
 
 Note. Remember the poisonous properties of arsenic compounds. 
 
 Examine a piece of " metallic " arsenic about the 
 size of a grain of wheat. Heat it on charcoal before 
 the blowpipe. Note that a white deposit of arsenic 
 trioxide appears on the charcoal. Write the reaction. 
 
 Make a small ignition-tube according to directions 
 given in Exercise 6. Place in it a small amount (equal 
 in volume to a coarsely broken half pea) of arsenic 
 trioxide, " white arsenic." Dry a piece of charcoal by 
 heating over the flame of a burner. Cool and cut it 
 into the form of a cylinder 2 cm. (f inch) long, having 
 just the diameter of the bore of the tube. Push this 
 charcoal plug into the ignition-tube to within about 
 13 mm. (-J- inch) of the arsenic trioxide. Heat the char- 
 coal as hot as possible, allowing the end of the tube 
 containing the oxide to extend out of the flame. When 
 the glass around the charcoal is nearly red-hot, hold 
 the tube in a more nearly vertical position, so that the 
 flame may strike both the charcoal and the white 
 arsenic at the same time. What forms on the cool 
 surface above the charcoal ? What reaction has taken 
 place between the vapor of arsenic trioxide and the 
 carbon ? When the tube is cool cut off the lower end 
 and remove the carbon. Now hold the tube at an 
 angle of 45 and heat again. What takes place ? Ex- 
 plain fully. 
 
 78 
 
ARSENIC. 79 
 
 (a) Arsine (Asff s ). 
 
 This compound is a deadly poison, hence it should 
 not be prepared by any except experienced chemists. 
 Study its properties in your text-book and describe it 
 fully. 
 
 (b) Comparison of Arsine with Stibine. 
 
 Perform the following experiment under the hood. 
 
 Stibine or hydrogen antimonide (SbH 3 ) may be made 
 as follows : Set up apparatus of the same general 
 character as shown in Fig. 13. See that the small 
 bottle is dry, and place in it granulated calcium chlo- 
 ride, in sufficient quantity to cover the bottom with a 
 layer about an inch deep. The tube from the gen- 
 erator should reach almost to the bottom of the bot- 
 tle. The calcium chloride serves to dry the gas. At- 
 tach at B a tube drawn out to a rather fine bore. Now 
 generate hydrogen as directed in Exercise 8, and after 
 all air is expelled light the gas. Hold in the flame a 
 cool porcelain dish. Is a black spot produced ? If 
 so, arsenic or antimony may be present in the reagents. 
 Now pour through the thistle-tube a few drops of a 
 solution of any antimony compound (as tartar emetic). 
 Does the hydrogen -flame change color? Hold the 
 dish in the flame. Is a spot deposited ? How could 
 you distinguish it from an arsenic spot ? (Consult 
 text). 
 
 (e) Show some of the points of similarity between 
 arsenic, antimony, and bismuth. 
 
 References: Clk., pp. 159-162, 247-252; Cly., pp. 
 134-137, 231 ; E., pp. 249-253 ; S., *pp. 242-250, 255- 
 258 ; S, and L., pp. 149-160 ; W., pp. 321-331, 336-339. 
 
EXERCISE 30. 
 SILICON ; BORON ; REVIEW OF NON-METALS. 
 
 (a) Silicon. 
 
 How is silicon prepared ? Give its chemical and 
 physical properties. (Consult text.) 
 
 To a solution of sodium silicate " water-glass " add 
 dilute hydrochloric acid to distinctly acid reaction. 
 Evaporate very cautiously to dryness in a small evap- 
 orating-dish on the wire gauze. The residue is silicon 
 dioxide (SiO a ) mixed with common salt. Is it (SiO 2 ) 
 soluble in water ? in acids ? Silicon dioxide (silica) 
 is the anhydride of the silicic acids. One of these has 
 the symbol H a SiO 9 . Compare its structure with that 
 of carbonic acid. 
 
 What is quartz? Quartz sand? Glass? How is 
 glass made ? 
 
 (b) Boron. 
 
 How is boron prepared ? Give its physical and 
 chemical properties. (Consult text.) 
 
 Dissolve lOgrms.of borax (sodium biborate, Na 2 B 4 O 7 ) 
 in 25 cc. boiling water. To the hot solution add 6 cc. 
 concentrated hydrochloric acid. On cooling crystals 
 of boric acid (H 3 BO 8 ) separate out. "Write the re- 
 action. 
 
 Filter off the boric acid from the mother liquor, and 
 dissolve a few crystals in 2 cc. of alcohol. Set fire to 
 the solution in a small evaporating-dish. Note the 
 color of the flame. 
 
 80 
 
SILICON; BORON; REVIEW OF NON-METAL8. 81 
 
 (c) Revieiu. 
 
 Explain the difference between metals and non- 
 metals. Is it possible to make a sharp distinction in 
 all cases ? 
 
 Make a list of all the non-metallic elements that you 
 have, studied, giving the atomic weights. Also make 
 a list of the compounds that you have studied, giving 
 formulas and molecular weights. (This list is not to 
 include complicated compounds, as sugar, starch, 
 starch iodide, etc.) 
 
 References: Clk., pp. 163-171; Cly., pp. 137, 138, 
 143-147 ; R, pp. 255-260 ; S., pp. 184-192 ; S. and L., 
 pp. 161-165; W., pp. 259-275. 
 
THE MOKE IMPORTANT METALS. 
 
EXERCISE 31. 
 
 THE ALKALI METALS. 
 
 Make a list of the metals of this group, arranged 
 in the order of their atomic weights. 
 
 (a) Sodium. 
 
 Put a few cc. of kerosene in a perfectly dry dish, 
 and ask your instructor to place in it a piece of sodium 
 as large as a small pea. Examine the metal. (Handle 
 alkali metals with pincers.) Describe its physical 
 properties. Cut off a little, free from kerosene by 
 pressing between filter-paper, and expose to the action 
 of the air. After twenty minutes examine the piece 
 What do you notice ? Why is sodium kept under 
 kerosene ? 
 
 Pour into a small evaporating-dish about 10 cc. of 
 distilled water. Now drop in about half the sodium 
 that you have and cover immediatety with a glass 
 plate. (This is to protect your eyes in case there 
 should be a slight explosion at the end of the reac- 
 tion.) What do you observe? Heat the solution 
 thus obtained nearly to boiling and add the rest of 
 the sodium. What takes place? To what is the 
 flame due ? To what is the color of the flame due ? 
 
 Test the solution, obtained by dissolving the two 
 portions of sodium, with red litmus" paper. Now add 
 hydrochloric acid till the solution is exactly neutral. 
 Evaporate to dryness and taste a little of the residue. 
 
 85 
 
86 THE MORE IMPORTANT METALS. 
 
 What is it? Write the. reactions, showing how you 
 have made salt from sodium. 
 
 (b) Potassium. 
 
 Ask your instructor for a piece of potassium about 
 the size of a grain of barley. Keep under kerosene 
 till you are ready to use it. Examine its physical 
 properties. Now drop it on cold water, covering the 
 dish as in the case of sodium. What do you notice ? 
 Which do you regard as the most active chemically, 
 sodium or potassium ? Which has the greater atomic 
 weight? Which would you expect to find the more 
 active chemically, lithium or caesium ? Why ? 
 
 (c) Solubility of the Salts of the Alkali Metals. 
 
 The following may be taken as representative com- 
 pounds : sodium sulphate, sodium carbonate, sodium 
 phosphate, potassium nitrate, potassium chloride, 
 potassium bichromate. Take six perfectly clean and 
 dry test-tubes and place in each as much of one of the 
 above-mentioned salts as will stand on the point of a 
 knife-blade. Add to each tube a little water, and 
 warm. Do you find them all soluble ? What do you 
 conclude in regard to the solubility of most of the 
 alkali compounds ? 
 
 (d) Flame Reactions. 
 
 Procure from your instructor a piece of platinum 
 wire about 2J inches long. Clean it before each test, 
 using a clean cloth moistened with distilled water. 
 
 Place one dror> of lithium chloride solution in a 
 clean dish. Moisten the wire in this solution and 
 hold in the colorless flame of the burner. Note color 
 
THE ALKALI METALS. 87 
 
 of flame. Try the same experiment with potassium 
 chloride ; with sodium chloride ; with any sodium 
 compound. 
 
 Name some of the salts of sodium and of potassium 
 that are of commercial importance. 
 
 References : Clk., pp: 183-192 ; Cly., pp. 216-218 ; 
 K, pp. 283-302 ; S., pp. 320-336 ; S. and L., pp. 288- 
 315; W,pp. 280-287. 
 
EXERCISE 32. 
 
 COMPOUNDS OF THE ALKALINE EARTHS (CALCIUM, STRON- 
 TIUM, AND BARIUM). 
 
 (a) Calcium Compounds. 
 
 To 2 grms. of precipitated chalk (calcium carbonate, 
 CaCO,) add dilute hydrochloric acid, drop by drop, 
 with constant stirring, till solution is just effected. 
 Now add a little more chalk to neutralize any excess 
 of acid. Heat and stir well in order that all of the acid 
 may come in contact with chalk. Add a little water 
 to replace what has evaporated, and filter from the 
 undissolved portion. Complete the reaction : 
 
 CaC0 3 + 2HC1 = CaCl, + . . . 
 
 Test the flame reaction of the solution of calcium 
 chloride just prepared. To a few drops of the calcium 
 chloride solution add an equal volume of sodium car- 
 bonate solution. The precipitate is calcium carbon- 
 ate. Write the reaction. Try the action of ammonium 
 carbonate. Reaction ? To the rest of the solution of 
 calcium chloride add sodium hydrate solution. Cal- 
 cium hydrate is precipitated. Write the reaction. 
 
 Fill a large test-tube half full of a clear solution of 
 calcium hydrate (lime-water). Generate carbon diox- 
 ide by the action of hydrochloric acid on marble, using 
 the apparatus shown in Fig. 13. The gas is to be 
 washed with water in the small bottle in order to free 
 it from traces of hydrochloric acid. The gas is now 
 
COMPOUNDS OF THE ALKALINE EARTHS. 89 
 
 passed into the lime-water till the precipitate which 
 forms at first is for the most part redissolved. Filter 
 the solution into a clean beaker and boil for a few 
 minutes. What do you notice ? Is this deposit cal- 
 cium carbonate ? Why do you think so ? We will 
 now study the reactions involved in the entire process. 
 You have already learned that calcium carbonate is 
 formed by the action of carbon dioxide on lime-water. 
 The next step is the solution of calcium carbonate 
 according to the reaction : 
 
 CaC0 3 + C0 2 + H a O = CaH 3 (CO,),. 
 
 This compound (acid calcium carbonate) remains in 
 solution till heated, when it breaks up according to a 
 reaction that is just the reverse of the one last given. 
 Write this reaction. Explain how water containing 
 carbon dioxide dissolves calcium carbonate from the 
 soil and rocks, becomes hard, and leaves a deposit of 
 " lime " in steam-boilers and tea-kettles. 
 
 (b) Strontium Compounds. 
 
 Test the flame reaction of strontium chloride. 
 
 To a few drops of strontium chloride solution add 
 the same volume of sodium carbonate solution. Com- 
 plete the reaction: SrCl t + Na,CO 3 = . . . 
 
 To another portion of the solution add a little dilute 
 sulphuric acid. Complete the reaction : 
 
 SrCl a + . .. = SrS0 4 +... 
 
 To a third portion add sodium Irydrate solution. 
 Strontium hydrate Sr(OH) 2 is precipitated. Write the 
 reaction. 
 
90 THE MORE IMPORTANT METALS. 
 
 (c) Barium Compounds. 
 
 Perform the same experiments with barium chloride 
 that you did with strontium chloride. Describe results 
 and write reactions. (The reactions are analogous.) 
 Ba is substituted for Sr.) 
 
 The formation of a precipitate indicates the forma- 
 tion of an insoluble or a difficultly soluble compound. 
 What, then, do you conclude as to the solubility of 
 most of the compounds of the alkaline earths? 
 
 References: Clk., pp. 205-212; Cly., pp. 220, 221; 
 R, pp. 303-318 ; S., pp. 308-316 ; S. and L., pp. 315- 
 325 ; W., pp. 288-293, 143-147. 
 
EXERCISE 33. 
 
 MAGNESIUM, ZINC, CADMIUM, AND MERCURY. 
 
 In eacli of the groups of metals that we have studied we have 
 found a striking similarity of properties. The grouping of the rest 
 of the metals is more or less arbitrary. Thus the metals considered 
 in this exercise do not resemble each other in so marked a degree as 
 do the alkaline earths. 
 
 (a) Magnesium. 
 
 Describe the metal. Treat a little of the metal (a 
 piece of magnesium ribbon 6 mm. long) with dilute hy- 
 drochloric acid. Try the same experiment with dilute 
 sulphuric acid. Magnesium chloride (MgCl,) and 
 magnesium sulphate (MgSO 4 ) are formed respectively. 
 Write the reactions. 
 
 Hold with the pincers a piece of magnesium 
 ribbon about 25 mm. (1 inch) long in the flame of the 
 burner till the magnesium is ignited. Magnesium 
 oxide is formed. Write the reaction. Prepare a 
 bottle of carbon dioxide and thrust into it a piece of 
 burning magnesium ribbon. Does the burning con- 
 tinue ? Are the products of combustion the same as 
 when magnesium burns in the air? This experiment 
 shows the affinity of magnesium for oxygen. 
 
 In a piece of charcoal make a hole large enough 
 to hold a half pea. Fill with magnesium oxide 
 slightly moistened with water. Now heat strongly 
 before the blowpipe, cool, moisten with one drop of 
 cobaltous nitrate, and heat again. Do you obtain a 
 
 91 
 
92 TEE MORE IMPORTANT METALS. 
 
 red-brown color? This is a test for magnesium 
 oxide. 
 
 (b) Zinc. 
 
 Put a little zinc in a test-tube and treat with dilute 
 hydrochloric acid. Repeat, using dilute sulphuric 
 acid. Reactions ? Heat a little zinc on charcoal in 
 the oxidizing-flame of the blowpipe. Note the white 
 coating of zinc oxide (ZnO) on the charcoal. Reac- 
 tion ? 
 
 Treat a little zinc oxide just as you did magnesium 
 oxide. Note the color when hot, when cold, after 
 treatment with cobaltous nitrate and heating a second 
 time. 
 
 How is zinc obtained from its ores ? 
 
 (c) Cadmium. 
 
 Procure from your instructor three pieces of cad- 
 mium. (The entire amount need not exceed grm. in 
 weight.) Heat one piece in an ignition-tube. Does 
 it melt at a comparatively low temperature ? Allow 
 to cool and then put on charcoal and heat in the oxi- 
 dizing-flame. What do you notice? What is the 
 color of cadmium oxide (CdO) ? 
 
 Test a piece of cadmium with dilute hydrochloric 
 acid. Cadmium chloride (CdCl a ) is formed. Reac- 
 tion? 
 
 Test another piece with dilute sulphuric acid. Re- 
 action? To a few drops of a solution of cadmium 
 chloride add ammonium sulphide. What is the color 
 of the cadmium sulphide (CdS). 
 
 (d) Mercury. 
 
 Give the physical properties of mercury. At what 
 temperature does it melt? Try the action of dilute 
 
MAGNESIUM, ZINC, CADMIUM, AND MERCURY. 93 
 
 hydrochloric acid on a drop of mercury. Does the 
 metal dissolve ? 
 
 To a little mercurous nitrate (HgNO,) solution add 
 a little dilute hydrochloric acid : mercurous chloride 
 (HgCl) is precipitated. Write the reaction. Re- 
 peat the same experiment, using mercuric nitrate 
 (Hg(NO 8 ) 2 ) solution. Is a precipitate formed? 
 Which, then, is soluble in water, mercurous chloride 
 (calomel) or mercuric chloride (corrosive sublimate) ? 
 
 Place in a few cc. of any mercury salt solution a 
 piece of bright copper ; withdraw after a few minutes 
 and rub with a cloth. Explain what you observe. 
 
 Make a list of the elements studied in this exercise 
 in the order of their atomic weights. Give their 
 atomic weights. Compare the metals in respect to 
 the following properties : specific gravity, melting, 
 point, ease with which they are attacked by acids. 
 
 Show in what relation these properties stand to 
 the atomic weights. 
 
 References : Clk., pp. 223-231 ; Cly., pp. 223, 224, 
 236-237; E., pp. 319-324, 330, 331; S., pp. 316, 317, 
 298, 300, 262, 263, 233, 237 ; S. and L., pp. 325-337, 
 347-350; W., pp. 301-305, 339, 340, 356-358. 
 
EXERCISE 34. 
 
 COPPEE, SILVER, AND GOLD. 
 (a) Copper. 
 
 To a solution of copper sulphate add a little cold 
 sodium hydrate solution. Copper hydrate (Cu(OH) 2 ) 
 is formed. Write the reaction. Add to a solution of 
 copper sulphate a drop or two of dilute ammonia. What 
 do you notice ? Now add excess of ammonia. What 
 color is produced ? To 2 or 3 cc. of water add a drop 
 of copper sulphate solution, then a drop of potassium 
 ferrocyanide solution. Note the color of the copper 
 ferrocyanide. This is a very delicate test for copper. 
 To a few drops of copper sulphate solution add 1 cc. 
 of a solution of tartaric acid, then sodium hydrate 
 solution till the solution is strongly basic. Now add 
 a little grape-sugar and boil. Cuprous oxide (Cu 2 0) 
 is precipitated. Describe it. To a little copper 
 sulphate solution add a drop of dilute hydrochloric 
 acid, then a piece of bright iron (wire nail). Examine 
 after a few minutes. How do you account for the 
 appearance of the nail ? 
 
 Heat a little bright copper in the flame of the 
 burner. Does it oxidize? Test the solubility of 
 copper in dilute nitric acid. Write the reaction. (See 
 Exercise 17.) 
 
 What use is made of copper in the arts? What 
 are some of the most important alloys of copper? 
 How is copper found in nature ? 
 
 94 
 
COPPER, SILVER, AND GOLD. 95 
 
 (5) Silver. 
 
 To a little silver nitrate solution add an equal 
 volume of dilute hydrochloric acid. Reaction ? Pour 
 off the liquid and dissolve the precipitate in ammonia. 
 Now add nitric acid. What appears? Collect the 
 precipitate on a very small filter, wash with distilled 
 water and allow to drain well. Now add to the pre- 
 cipitate its own volume of dry sodium carbonate, and 
 roll the filter and contents into a ball (size of a pea). 
 Heat this on charcoal before the blowpipe till the 
 paper is consumed. If the silver appears in scattered 
 deposits, scrape them together and fuse into a single 
 bead. Does silver oxidize when heated in the air? 
 Try the solubility of the silver bead in nitric acid. 
 Why is silver classed among the noble metals ? What 
 is " coin silver " ? " sterling silver " ? 
 
 (c) Gold. 
 
 See text-book for the properties of gold. 
 
 Does gold oxidize when heated ? Does it dissolve 
 in any simple acid? Compare it with silver and 
 with copper in these respects. What is the composi- 
 tion of the alloy of which gold coins are made? 
 What is meant by the term 18-carat gold ? 
 
 References: Clk., pp. 275-279, 196-203, 280-281; 
 Cly., pp. 233-236, 237-245 ; E., pp. 325-329, 332-336, 
 378-381 ; S., pp. 258-261, 228-233, 266-267 ; S. and 
 L., pp. 341-346, 350-356, 383-385; W., pp, 340-343, 
 349-356, 369-361. 
 
EXERCISE 35. 
 
 ALUMINIUM (OR ALUMINUM). 
 
 Procure two small pieces of the metal from your in- 
 structor. Test the solubility (using one piece) with 
 dilute hydrochloric acid. Aluminium chloride (A1C1 3 ) 
 remains in solution. Write the reaction. Test the 
 solubility of aluminium in dilute sodium hydrate solu- 
 tion. Sodium aluminate (NaAlO 2 ) remains in solu- 
 tion. Write the reaction. Describe the physical 
 properties of aluminium. 
 
 To a solution of aluminium sulphate (Al a (S0 4 ),) add 
 ammonium hydrate. Aluminium hydrate (Al(OH) a ) 
 is precipitated. Write the reaction. Filter and 
 heat the precipitate on charcoal before the blow- 
 pipe, moisten with a little cobaltous nitrate and heat 
 again. Note the color. This is a test for aluminium. 
 
 Alum is a good example of a "double salt." 
 
 Dissolve with the aid of heat 10 grms. of aluminium 
 sulphate in as little water as will effect solution. 
 Now dissolve 2.6 grms. of potassium sulphate in the 
 same manner and mix the hot saturated solutions of 
 the two salts. Crystals of alum (A1K(SO 4 ) 3 .12H 3 O) 
 will form on cooling. Filter off the crystals from the 
 mother-liquor and show to the instructor. How can 
 you show that they contain aluminium ? (See reac- 
 
 96 
 
ALUMINIUM. 97 
 
 tions above.) How can you prove that they contain 
 potassium ? (See flame-test, Exercise 30.) 
 
 How is aluminium reduced from its ores ? Give 
 uses of the metal ; of its alloys. 
 
 References: Clk., pp. 232-236; Cly., pp. 221-223 
 E., pp. 339-348 ; S., pp. 286-290; S. and L., pp. 357- 
 363 ; W., pp. 313-317. 
 
EXERCISE 36. 
 TIN AND LEAD. 
 
 (a) Tin. 
 
 Give the physical properties of the metal. Put 
 about | grm. of granulated tin into a test-tube and 
 add hydrochloric acid. The tin dissolves in the acid, 
 forming a solution of stannous. chloride (SnCl,). Af- 
 ter the greater part of the tin has dissolved, pour off 
 the solution from the undissolved metal. To this 
 solution add a few drops of mercuric chloride solu- 
 tion. Now heat. The precipitate varies from white 
 to grayish black, depending on the temperature and 
 the proportion of each reagent added. The reactions 
 may be expressed as follows : 
 
 2HgCl 2 + SnCl a = 2HgCl (white ppt.) + SnCl 4 (sol.). 
 2HgCl + SnCl, = 2Hg (dark gray) + SnCl 4 (solution). 
 This is a delicate test for both tin and mercury. 
 
 To a little tin add moderately concentrated ni- 
 tric acid. What do you notice? Metastannic acid 
 (HjSnOj)* is formed. Is it soluble in water ? Filter, 
 wash and drain well. Now heat a little in a porcelain 
 crucible to a high temperature. Stafinic oxide is 
 formed. Write the reaction. 
 
 What use is made of tin in the arts? What is 
 bronze ? 
 
 (b) Lead. 
 
 Dissolve \ grm. of lead in nitric acid in the follow- 
 ing manmer : Place the lead in an evaporating-dish 
 
TIN AND LEAD. 99 
 
 containing a few cc. of water. Heat to boiling and 
 add concentrated nitric acid till vigorous action takes 
 place. Now set under the hood and allow to stand till 
 action nearly ceases. If undissolved lead is present, 
 add a little more acid and warm. If this does not 
 cause action to begin again, add a little more water. 
 In order to dissolve lead readily there must be acid 
 enough to unite with the lead, and water enough to 
 hold in solution the lead nitrate formed. When solu- 
 tion is effected, evaporate nearly to dryness and dis- 
 solve the residue in 500 cc. of water. Suspend in this 
 solution a strip of zinc and allow it to remain for an 
 hour. What do you notice ? Complete the reaction : 
 
 Zn + Pb(NO 3 ) a = Pb + . . . 
 
 To a solution of lead nitrate (Pb(NO 8 ) a add dilute 
 sulphuric acid. Write the reaction. To another por- 
 tion of the nitrate solution add a solution of potassium 
 chromate (K 2 CrO 4 ). Lead chromate is formed. Write 
 the reaction. 
 
 Warm a little red lead (Pb,O 4 ) with dilute nitric acid 
 in excess. Brown lead peroxide (PbO 2 ) is left undis- 
 solved. 
 
 How is lead reduced from its ores? What use 
 is made of lead in the arts ? What are some of the 
 more important alloys of lead ? 
 
 References: Clk., pp. 239-245; Cly., pp. 230, 232, 
 233; E., pp. 349-357; 8, pp. 251-254, 224-228; S. 
 and L., pp. 381-383, 337-341 ; W., pp. 331-335, 334- 
 349. 
 
EXERCISE 37. 
 
 CHROMIUM. 
 
 (a) Chromates. 
 
 In these compounds chromium has an acid character. Chromic 
 acid (hydrogen chromate (H 2 CrO 4 )) is known only in solution. The 
 salts of this acid are similar in structure and crystalline form to the 
 salts of sulphuric acid. 
 
 Dissolve a few crystals of potassium chromate in 
 water, and to separate portions add in solution : 
 silver nitrate, barium chloride, lead nitrate. Reaction 
 for silver nitrate : 
 
 K 2 CrO 4 + 2AgN0 3 = 2KNO 9 + Ag 9 CrO 4 . 
 
 Now write the other two reactions, remembering that 
 one atom of lead or barium can replace two atoms of 
 potassium. 
 
 To about 1 cc. of potassium chromate solution add 
 a few drops of any dilute acid on your desk. Note 
 change of color. Potassium bichromate is formed. 
 Complete the following : 
 
 2K a CrO 4 + 2HC1 = K,Cr,O 7 + . . . 
 
 To this solution add a solution of potassium hydrate 
 till the color just changes to yellow. Potassium 
 chromate (K 2 CrO 4 ) is again formed. Write the 
 reaction. 
 
 (b) Chromic Compounds. 
 
 When chrornates are reduced, i.e. lose oxygen, the acid character 
 of chromium disappears. Chromium in chromic compounds has a 
 basic character. 
 
 100 
 
CHROMIUM. i~ 5 - 
 
 To about 1 cc. of a solution of potassium bichromate 
 add a little concentrated hydrochloric acid and a few 
 drops of alcohol. Warm and note change of color. 
 Eepeat, using a little oxalic acid instead of alcohol. 
 
 To a solution of chrome alum add ammonia. The 
 reaction is as follows : 
 
 CrK(S0 4 ) 9 + 3NH 4 OH 
 
 - KNH 4 S0 4 + (NHg),S0 4 + Cr(OH), 
 
 Mix a little ( grm.) dry sodium carbonate with an 
 equal quantity of potassium nitrate and half as much 
 chrome alum. Heat strongly in a porcelain crucible 
 for some time, cool and dissolve in water. If the 
 oxidation is complete the solution will appear yellow. 
 To the solution add dilute nitric acid till it just begins 
 to turn orange-red. Add now a few drops of silver 
 nitrate solution ; a red-brown precipitate shows the 
 presence of a chromate. 
 
 Fuse a piece of platinum wire into a piece of glass 
 tube ; the shape is shown in Fig. 22. 
 
 FIG. 22. 
 
 Heat the wire loop in the flame, and bring it into 
 contact with a small crystal of borax. Fuse this to a 
 globule, continuing the process till you have a clear 
 bead of borax glass just large enough to be held in the 
 loop. 
 
 Fuse into this bead a minute quantity of chrome 
 alum, just enough to give a decided color, not enough 
 to make it opaque. "What do you notice ? This is a 
 delicate test for chromium. 
 
 References : Clk., pp. 252-256 ; E., pp. 372-375 ; S., 
 pp. 282-285 ; S. and L., pp. 378, 379 ; W., pp. 317-320. 
 
EXERCISE 38. 
 
 MANGANESE. 
 
 (a) Oxidizing Action of Permanganates. 
 
 Dissolve a crystal of potassium permanganate 
 (KMnO 4 ) in 10 cc. of water. Place in a beaker and 
 heat nearly to boiling. To the hot solution add, 
 a drop at a time, a solution of oxalic acid containing 
 a little sulphuric acid. Is the color discharged? 
 Repeat, using a solution of ferrous sulphate containing 
 sulphuric acid in place of the oxalic acid solution. 
 
 To a few crystals of potassium permanganate in an 
 evaporating-dish add a few drops of concentrated sul- 
 phuric acid. Put 1 cc. of strong alcohol in a dry 
 beaker and pour it upon the mixture just made. 
 What do you notice ? 
 
 To a few crystals of potassium permanganate in a 
 test-tube add concentrated hydrochloric acid. Is the 
 acid oxidized ? If so, what gas is liberated ? How do 
 you recognize it? 
 
 (&) Manganous Compounds, 
 
 To a solution of manganous sulphate add sodium 
 hydrate. Manganous hydrate is formed. Complete 
 the reaction : MnSO 4 + 2NaOH = . . . 
 
 Allow the precipitate to stand exposed to the air till 
 it changes in color. Manganic hydrate (Mn(OH) 8 ) is 
 
 formed. 
 
 102 
 
MANGANESE. 103 
 
 To a solution of manganous sulphate add a solution 
 of ammonium sulphide. Manganous sulphide (MnS) 
 is precipitated. Describe precipitate and write re- 
 action. 
 
 Test any manganese compound in the borax bead. 
 (See Exercise 37.) What color is imparted to the 
 borax glass ? 
 
 What are some of the uses of manganese com- 
 pounds ? 
 
 References: Clk., pp. 262-264; K., pp. 369-371 ; S., 
 pp. 295-298 ; S. and L., pp. 363-365 ; W., pp. 298-301. 
 
EXERCISE 39. 
 
 IKON, COBALT, NICKEL, AND PLATINUM. 
 
 (a) Iron in Ferrous Compounds. 
 
 Put about 3 grms. of iron turnings into a test-tube 
 and add, a little at a time, about 10 cc. dilute hydro- 
 chloric acid. Ferrous chloride (FeCl 2 ) is formed. 
 Reaction. Allow to stand till action nearly ceases, 
 then pour off the solution, about 1 cc. at a time, and 
 test its action with solutions of the following reagents : 
 (1) sodium hydrate ; (2) potassium ferrocyanide ; (3) 
 potassium ferricyanide. Describe results. Write re- 
 action for (1). Allow this precipitate to stand exposed 
 to the air. Ferric hydrate (Fe(OH) 3 ) is formed. 
 
 (b) Iron in Ferric Compounds. 
 
 Try the action of ferric chloride (FeCl,) solution on 
 reagents (1), (2), and (3). Describe results and write 
 reaction for (1). To about 1 cc. of a solution of fer- 
 rous chloride add a few drops of concentrated nitric 
 acid and boil. The solution should now be light 
 yellow in color. If it is green or dark, repeat the 
 process. Avoid an excess of acid. Now prove by the 
 action of reagents (1), (2), and (3) that ferrous iron has 
 been oxidized to ferric iron. 
 
 What are the most important ores of iron ? What is 
 cast iron ? wrought iron ? steel ? 
 
 104 
 
IRON, COBALT, NICKEL, AND PLATINUM. 105 
 
 (c) Cobalt 
 
 To 1 cc. of a solution of cobaltous chloride add 
 sodium hydrate solution and boil. Cobaltous hydrate 
 is precipitated. Write the reaction. (See analogous 
 reation of FeCl a -f 2NaOH.) What color is imparted 
 to the borax bead by cobalt compounds? 
 
 (d) Nickel 
 
 Treat a solution of nickel sulphate (NiSO 4 ) with 
 sodium hydrate solution. What is formed ? Keaction. 
 What color is imparted to the borax bead by nickel 
 compounds ? 
 
 What use is made of nickel in the arts ? What are 
 some of the most important alloys of nickel? Of 
 what does "nickel" used for coinage consist? 
 
 (e) Platinum. 
 
 What properties of platinum have you observed? 
 Why is it valuable for use in the laboratory ? How 
 is it found in nature ? 
 
 JReferences: Clk., pp. 264-271, 273, 274, 282-284; 
 Cly., pp. 224-230, 244; E., pp., 358-368, 376-378; S., 
 pp. 275-282, 290-295, 268, 269 ; S. and L., pp. 366, 
 378, 385-388 ; W., pp. 306-313, 294-298, 361. 
 
SOME FAMILIAR HYDROCARBONS 
 AND THEIR DERIVATIVES. 
 
 SO-CALLED ORGANIC COMPOUNDS. 
 
EXERCISE 40. 
 
 SOME HYDROCARBONS. 
 
 (a) The Methane Series. 
 
 This series has the general formula C n H 2n + 2 . It is 
 rather difficult to prepare the lower members. Con- 
 sult text and reference-books for the preparation and 
 properties 'of the first member, methane (CH 4 ). Ex- 
 amples of the higher members are benzine, gasoline, 
 kerosene, and paraffine. 
 
 The greater part of gasoline consists of heptane 
 (C 7 H 16 ) and octane (C 6 H ]8 ). Place four drops of gaso- 
 line in an evaporating-dish. (Keep bottle of gasoline 
 away from flames.) Place the dish under the hood 
 and apply a lighted splinter. Note the character 
 of the flame. 
 
 Now repeat the same experiment, using kerosene 
 instead of gasoline. (Kerosene consists principally of 
 hydrocarbons, C ia H a8 to C ]6 H 34 inclusive.) Which 
 can you light the most readily, gasoline or kerosene ? 
 Which burns with the higher flame? Which flame is 
 the more sooty ? What relation does the number of 
 carbon atoms bear to the volatility of the hydrocarbon? 
 
 When any hydrocarbon is completely burned, water 
 and carbon dioxide are the only, products formed. 
 Write the reaction representing the combustion of 
 hexane (C e H 14 ). What is the composition of American 
 petroleum? (See reference-books or cyclopedia.) 
 
 109 
 
110 SOME FAMILIAR HYDROCARBONS. 
 
 (b) Acetylene (C t H t ). 
 
 This hydrocarbon belongs to the series C n H 2n _ 2 . 
 
 Fill a test-tube one fourth full of water and drop 
 into it two or three pieces of calcium carbide (CaC a ) as 
 large as peas. Light the escaping gas. Note the ap- 
 pearance of the flame. "Write the reaction repre- 
 senting the combustion of acetylene. 
 
 After action in the tube has ceased test the con- 
 tents of the tube with red litmus paper. Have you 
 reason to think that calcium hydrate (Ca(OH) 3 ) is 
 present? If so, write the reaction representing the 
 action of water on calcium carbide resulting in the 
 liberation of acetylene. 
 
 References: Oik., pp. 79-83, 296, 297 ; Cly., pp. 183- 
 186; E., pp. 384-389; S., pp. 132-135; S. and L., 
 pp. 196-206, 238, 239 ; W., pp. 363-370. 
 
EXERCISE 41. 
 
 SOME HALOGEN DERIVATIVES OF THE HYDROCARBONS. 
 
 (a) Chloroform (CHCl,). 
 
 Chloroform may be made by treating methane with 
 chlorine. It is regarded as methane in which three 
 chlorine atoms have been substituted for three hydro- 
 gen atoms. 
 
 Pour about 3 cc. of chloroform into a test-tube 
 provided with a cork stopper, and use for the follow- 
 ing tests : Put a few drops into a dry test-tube and 
 warm. Note the odor. Will the vapor burn ? To a 
 few cc. of water in a test-tube add a few drops of 
 potassium iodide solution and a minute crystal of 
 iodine. When solution is effected add a few drops 
 of chloroform to the colored solution, shake vigor- 
 ously, and allow to settle. What do you notice ? Is 
 chloroform a good solvent for iodine ? for gums and 
 oils? Try its action on a little paraffine. What is 
 the principal use of chloroform ? 
 
 (b) lodoform (CHI 3 ). 
 
 Place in a test-tube 1 cc. of ordinary (ethyl) alcohol 
 and add 2 grms. of iodine. Now dissolve in a small 
 beaker or test-tube about 3 grms. of potassium car- 
 bonate (or sodium carbonate) in a small quantity of 
 hot water. Add this to the iodine in the alcohol, 
 drop by drop, till the brown color disappears. Boil 
 the mixture till any pieces of iodine that may be in 
 
 111 
 
112 SOME FAMILIAR HYDROCARBONS. 
 
 the bottom of the tube are dissolved. If the solution 
 becomes brown, add a drop or two more of the carbon- 
 ate solution. Now heat to boiling, set aside, and 
 allow to cool. Yellow crystals of iodoform should 
 separate out. For what is iodoform used ? 
 
 References : Clk., pp. 302 ; R., pp. 387, 388 ; S. and L., 
 pp. 197, 198 ; W., pp. 366. 
 
EXERCISE 42. 
 
 ALCOHOL. 
 
 An alcohol may be defined as a hydrocarbon in which hydrogen 
 (H) has been replaced by hydroxyl (OH). 
 
 (a) Methyl Alcohol (CH 3 OH). 
 
 Procure 1 cc. of methyl alcohol (or wood spirit) 
 and note odor. Draw some of the vapor (not the 
 liquid) into the mouth and note the taste. Do you 
 think that this alcohol would admit of use in bever- 
 ages ? What is " methylated spirit " ? Will methyl 
 alcohol burn ? If so, write the reaction. 
 
 (b) Ethyl Alcohol (C\H 6 OH). 
 
 Put 20 grms. of commercial glucose or 30 grms. of 
 " corn-syrup " into a 250-cc. flask, add about 150 cc. 
 of water and one fourth of a cake of " compressed " 
 yeast. Fermentation should begin promptly, accord- 
 ing to the reaction : 
 
 C 6 H 12 6 = 2C,H 6 OH + 2C0 2 . 
 
 Grape-sugar Alcohol Carbon dioxide 
 
 To prove that carbon dioxide is given off conduct 
 the escaping gas into lime-water as shown in Fig. 23. 
 Cover the lime-water with a thin layer of kerosene to 
 protect it from the action of carbon dioxide in the 
 air. Be sure that the cork in the flask is perfectly 
 tight, otherwise the gas will gradually diffuse into the 
 
 113 
 
114 
 
 SOME FAMILIAR HYDROCARBONS. 
 
 FIG. 23. 
 
 air instead of passing into the lime-water. Set aside 
 for several days. Does the lime-water become cloudy ? 
 If so, give the reaction. Now filter the contents of the 
 flask. The filtrate consists of some un- 
 changed glucose, alcohol, and traces of 
 other products dissolved in a large ex- 
 cess of water. The alcohol may be ob- 
 tained in purer condition and more 
 concentrated form by distilling. 
 
 Set up apparatus as shown in Fig. 18. 
 Pour into the retort about one half as 
 much of the filtrate as it will hold and 
 then drop in a few pieces of granulated zinc to 
 prevent " bumping." 
 
 Distil over, very cautiously, about one fourth of 
 the liquid in the retort, keeping the test-tube used as 
 a receiver well cooled. This distillate contains nearly 
 all the alcohol of the liquid placed in the retort along 
 with considerable water. Save the distillate ; throw 
 away the liquid remaining in the retort. Repeat the 
 process till all the alcohol in the filtrate has been dis- 
 tilled off. If directions have been followed, you have 
 now distilled off 40 to 50 cc. of dilute alcohol. Now 
 wash the retort, and in it place this dilute alcohol. 
 Distil off about 10 cc. You should now have the al- 
 cohol in a fairly concentrated form. Put 1 cc. of this 
 alcohol into a test-tube, add a few crystals of iodine, 
 and then potassium carbonate solution. See method 
 of making iodoform in Exercise 40, The formation 
 of iodoform shows the presence of alcohol. 
 
 Put the rest of the alcohol in a beaker and gradually 
 heat to boiling. Apply a light to the vapor. If the 
 alcohol does not contain too much water its vapor will 
 burn. Write the reaction. 
 
ALCOHOL. 115 
 
 Note. Conditions affecting Fermentation. The yeast must be fresh. 
 " Compressed " yeast gives better results than dry yeast. Fermen- 
 tation requires air at the start, hence do not make the test for carbon 
 dioxide till the gas begins to come off freely. The proper tempera- 
 ture is 20-30 C. (68-86 F.). Sunlight is unfavorable. Disin- 
 fectants, as certain salts, carbolic acid, etc., kill the yeast-cells. 
 Impure sugars or syrups contain albuminoids and phosphates, hence 
 they ferment more readily than pure sugars. 
 
 References: Clk., pp. 298-300; Cly., pp. 186-189; 
 K, pp. 389-391, 400, 401; S. and L., pp. 210-214; 
 W., pp. 865, 366, 370, 371. 
 
EXERCISE 43. 
 SOME FATTY ACIDS. 
 
 These acids are called "fatty acids" because some of the higher 
 members, combined with glycerin, constitute a considerable portion 
 of animal and vegetable oils. Hence the hydrocarbons from which 
 they are derived are called " fatty " hydrocarbons. 
 
 (a) Acetic Add (H(C 9 H,O t )). 
 
 Set up apparatus as in Fig. 18. Place a few pieces 
 of glass in the retort and add about 30 cc. of strong 
 vinegar. Distil off the greater part of the liquid. 
 Taste the distillate. 
 
 Try its action on blue litmus paper ; on sodium 
 carbonate solution. Complete the reaction : 
 
 Na,CO, + 2H (C.H.O.) = . . . 
 
 To a little of the distillate add a few drops of ferric 
 chloride solution. Note color of solution. 
 
 (b) Soap. 
 
 Soap consists principally of the sodium (or potassium) salts of the 
 higher fatty acids. Thus we may assume that a pure white soap 
 consists of sodium palmitate (Na (C 16 H3i0 2 ) ) and sodium stearate 
 (Na(Ci 8 H 35 02)). Since this latter compound predominates we will 
 use it in writing all reactions in this section. 
 
 Weigh out 5 grms. of any white soap (" Ivory" soap 
 is good), and cut into fine shavings. Dissolve these in 
 100 cc. of distilled water, heating if necessary. If the 
 solution is not perfectly clear, filter. 
 
 Make a saturated solution (5 cc.) of common salt, 
 
 116 
 
SOME FATTY ACIDS. 117 
 
 and to this solution add an equal volume of the soap 
 solution. What do you notice ? Soap is not soluble, 
 in brine. Explain what use is made of this fact in 
 soap manufacture. 
 
 To another portion of the soap solution add a few 
 drops of magnesium sulphate. Eesult ? 
 
 Complete the reaction MgSO 4 + 2Na(C 18 H 86 O a ) = 
 
 Is the precipitate soluble in water? Explain how 
 magnesium sulphate makes water " hard." 
 
 Prepare a solution of acid calcium carbonate. (See 
 Exercise 32.) Test a little of the solution with the 
 soap solution. Is a precipitate formed ? 
 
 The reaction is : 
 
 CaH,(CO,) J +2NaC 18 H a A=Ca(C 1 .H 31 0,),+2NaHCO,. 
 
 Now boil the rest of the acid calcium carbonate 
 solution for several minutes and filter. Test the filtrate 
 with soap solution. Do you now get a precipitate? 
 Explain. What is temporatory hardness in water? 
 
 To the rest of the soap solution add hydrochloric 
 acid to decidedly acid reaction. The precipitate con- 
 sists of stearic acid (with other acids). Write the re- 
 action. Is this acid soluble in water? 
 
 References: Clk., pp. 303-306, 319-321; Cly., p. 
 206; R, pp. 393-396; S. and L., pp. 215, 216, 224- 
 227; W., pp. 372, 373. 
 
EXERCISE 44. 
 SOME FAMILIAR CARBOHYDRATES. 
 
 (a) Glucose or Grape-sugar (C 6 H^O^). 
 
 Prepare Fehling's test for glucose as follows : Dis- 
 solve about 1.8 grms. of crystallized copper sulphate in 
 25 cc. of water. Label this solution "I." Dissolve 8 
 grms. of Rochelle salt (sodium potassium tartrate) in 
 25 cc. of water. To this solution add 25 grms. of pure 
 (solid) sodium hydrate and heat gently till solution is 
 effected. Label this solution "II." 
 
 To 5 cc. of solution " II " add an equal quantity of 
 solution "I." Place in a small beaker and heat to 
 boiling. If the reagents are pure, no change will be 
 noticed. Now add a little glucose and heat again. 
 What do you notice ? Cuprous oxide, containing more 
 or less water, is precipitated. 
 
 (b) Cane-sugar (C^OJ. 
 
 Warm a few crystals of cane-sugar with a drop of 
 concentrated sulphuric acid and note result. Test 
 with Fehling's solution as in (a), using cane-sugar in- 
 stead of glucose. If no precipitate is formed, test 
 with a few drops of a solution of cane-sugar that has 
 been boiled with a drop of concentrated hydrochloric 
 acid. Describe results. Explanation : Under the in- 
 fluence of the acid we have 
 
 C..H..O,, + H.O = C 6 H, A + C.H..O.. 
 
 Cane-sugar + Water = Grape-sugar + Fruit-sugar. 
 
 118 
 
SOME FAMILIAR CARBOHYDRATES. 119 
 
 (c) Starch (C t N 10 6 ) x . 
 
 How can you detect starch by means of iodine? 
 (See Exercise 22.) Prove that a sample labelled 
 " starch " really contains starch. Work out the details 
 of the test for yourself. Describe results fully. 
 
 Does starch give a precipitate with Fehling's solu- 
 tion ? Can you obtain a precipitate by first converting 
 starch into glucose ? Proceed as follows : Put a little 
 starch into a test-tube and add a few drops of con- 
 centrated sulphuric acid. Allow to stand for a few 
 minutes, then add a little water and boil. 
 
 Does a little of this reduce Fehling's solution ? 
 
 (d) Cellulose (C 6 H 10 6 ) V . 
 
 Filter-paper and absorbent cotton are examples of 
 nearly pure cellulose. Is cellulose soluble in water 
 or dilute acids ? Can it be converted into glucose ? 
 Try as follows : Put a little filter-paper (a round filter 
 7 cm. in diam.) into a perfectly dry beaker and add 1 
 cc. of concentrated sulphuric acid. Using a glass rod, 
 thoroughly stir the paper into at hick paste. Allow to 
 stand for a few minutes, then add 2 cc. of water and 
 boil. Nearly neutralize with solid sodium carbonate, 
 adding a little water from time to time in quantity suf- 
 ficient to dissolve the greater part of the sodium sul- 
 phate that is formed. Test this solution with Fehling's 
 solution. 
 
 The following experiment is to be performed if ice 
 or snow is procurable. Set a small beaker in a dish 
 containing pieces of ice or snow. A/M 10 cc. concen- 
 trated nitric acid and allow to cool. Now pour in 20 cc. 
 concentrated sulphuric acid and stir with a glass rod. 
 Allow the mixed acids to cool and then introduce a 
 
120* SOME FAMILIAR HYDROCARBONS. 
 
 tuft of absorbent cotton equal in volume to that of the 
 mixed acids. Allow to stand for 15 minutes, remove 
 with a glass rod and wash thoroughly. Set aside and 
 allow to dry. Compare it with absorbent cotton. 
 Place an equal amount of absorbent cotton near it and 
 apply a lighted splinter to each. What do you. notice? 
 For what is nitrocellulose used ? What is gun-cotton ? 
 
 Why are the compounds in this exercise called 
 carbohydrates ? 
 
 References: Clk., pp. 322-328; Cly., pp. 203,204; 
 K., pp. 402-408 ; S. and L., pp. 253-269. 
 
EXERCISE 45. 
 
 A FEW AROMATIC OR BENZENE DERIVATIVES. 
 
 (a) Benzene or Benzol (O 6 H 6 ). 
 
 This compound is not to be confused with commercial " benzine." 
 
 Note the odor of benzene. Procure a few drops in 
 an evaporating-dish and apply a lighted splinter. 
 Note the appearance of the benzene flame. 
 
 (b) Nitrobenzene (C 6 H,NO,). 
 
 Perform this experiment under the hood. See that no lighted 
 burners are near. Avoid inhaling the fumes. 
 
 Put 5 cc. concentrated nitric acid into a small flask 
 and add an equal volume of benzene. Now add, a drop 
 at a time, 2 cc. concentrated sulphuric acid, stirring 
 constantly. In case the mixture becomes hot so as to 
 seem to boil, place the flask in cold water. When all 
 the sulphuric acid has been added, place the flask in a 
 dish containing water that has been heated to boiling. 
 Allow to stand for five minutes, and then pour the 
 contents of the flask into cold water. Nitrobenzene 
 sinks to the bottom. Pour off the acid solution above 
 it and add more water. Stir well, allow to settle, and 
 pour off the water. Note the color and odor of nitro- 
 benzene. Keaction : C 6 H 6 + HNO 3 ^ C 6 H B NO 2 + H,O. 
 The sulphuric acid helps to remove the water. 
 
 121 
 
122 SOME FAMILIAR HYDROCARBONS. 
 
 (c) Aniline (C&NHJ. 
 
 Aniline is prepared by reducing nitrobenzene with 
 iron and hydrochloric acid. Hydrogen is generated, 
 which reacts as follows : 
 
 C 6 H B NO, + 6H = C 6 H B NH, + 2H 3 O. 
 
 As it is troublesome to separate aniline from the 
 products formed, it is better to use prepared aniline 
 for the following experiments : Place a few drops 
 of water in a test-tube and add an equal volume of 
 cone, sulphuric acid. To this acid solution add a few 
 drops of aniline, mix, and cool. Aniline sulphate is 
 formed. Describe it. 
 
 Put 2 grms. of fresh bleaching-powder in 10 cc. of 
 water. Stir well, allow to stand for five minutes, and 
 filter. Dissolve a drop or two of aniline in 10 cc. of 
 water and add this to the bleaching-powder solution. 
 Note color. This is a test for aniline. 
 
 (d) JKosaniline. 
 
 Put a few drops of aniline with a few crystals of 
 fcoluidine in a test-tube. Add a few crystals of mer- 
 curic chloride (corrosive sublimate) and heat for a 
 moment over the open flame. Cool, add a drop of 
 cone, hydrochloric acid, then 1 cc. of alcohol. Now 
 dilute with water, and note the .color imparted to the 
 water. 
 
 References : Clk., pp. 329-337 ; E., pp. 408-411 ; S. 
 and L., pp. 240-242. 
 
APPENDIX. 
 
 INFORMATION FOR SCHOOLS NEEDING EQUIPMENT FOR 
 TEACHING CHEMISTRY. 
 
APPENDIX. 
 
 THE following is a list of the apparatus called for by 
 the manual. As it stands the list is complete for one 
 student. It is desirable that all items marked * 
 should be multiplied by the number of students who 
 are expected to work at the same time. 
 
 The Denver Fire-clay Company, 3101-3141 Champa 
 Street, Denver, Colo., will supply apparatus and chemi- 
 cals at the prices given. 
 
 * Asbestos plate, X 4" $0.05 
 
 Balloon, toy , * 05 
 
 * Beakers, lipped, Nos. 0, 2, and 4 31 
 
 * Blowpipe, plain, brass, 10" 06 
 
 * Bottles, 8 and 4 oz., wide mouth, 2 each 15 
 
 * Burner, Bunsen, w. 2 feet hose 32 
 
 * Burner, fishtail only .10 
 
 * Burette clamp 10 
 
 Corks, asst'd, 2 doz 10 
 
 * Cork-borers, set of 3 42 
 
 * Copper wire, 10 gauge, 3 feet 05 
 
 * Crucible, pore., w. cover, 1J", E. M., No. 8 09 
 
 * Evaporating-dish, pore., 3" 09 
 
 Files, round and three-cornered 13 
 
 * Flasks, flat bottom, 250 and 500 cc 18 
 
 * Funnel, 3" 07 
 
 * Gauze, wire, 4" X 4" 05 
 
 * Glass rod, & diam., 9* long .05 
 
 125 
 
126 APPENDIX. 
 
 * Glass plate, window-glass, 3" X 3* $0.05 
 
 Graduate, 50 cc. cylinder 23 
 
 * Leaden dish, 2" diam 08 
 
 Magnet, horseshoe, 2" 05 
 
 Magnifying-glass, 1 glass, rubber case 37 
 
 Mortar and pestle, W. W., 4 oz 19 
 
 * Pincers, 4" 05 
 
 * Picture-wire, 6" No charge. 
 
 Platinum wire, 24 gauge, 3" , , . , , .24 
 
 Platinum-foil, med., Y X I" 60 
 
 * Pneumatic trough, 5" X 1" X 10" 84 
 
 Reagent bottles, set of eight, 4 oz. : 
 
 Hydrochloric acid cone. 
 Hydrochloric acid dil. 
 Sulphuric acid cone. 
 
 r 
 
 .88 
 
 Sulphuric acid dil. 
 Nitric acid cone. 
 Nitric acid dil. 
 Sodium hydrate. 
 Ammonia. 
 
 * Retort, 50 cc. with glass stopper 20 
 
 * Ring-stand, w. 2 rings 34 
 
 * Test-tube rack for 6 tubes, w. pins 25 
 
 * Test-tubes, 16 X 160 mm., 1 doz 16 
 
 * Test-tube, one, 25 X 200mm . . 03 
 
 * Thistle-tube, 14" 06 
 
 * Tube, rubber, J", 6 inches 05 
 
 * Tubes, soft glass, V i. d., 5 tubes 10 
 
 * Tube, hard glass, " o. d 05 
 
 * Triangle for 1 J" crucible, pipe-stem 04 
 
 * Watch-glasses, iy 05 
 
 Alcohol-lamp, 2 oz 12 
 
APPENDIX. 127 
 
 In addition to the apparatus just listed a number of 
 bottles of various sizes, and a few large beakers and 
 evaporating-disbes, should be included in the order. 
 These articles will be needed in making solutions 
 of reagents. 
 
 The laboratory should also be provided with a 
 balance accurate to .05 grm., a set of weights, an 
 apparatus for distilling water, and a water-bath. 
 
 O 
 
 FIG. 24. 
 
 In case the building is heated by steam, water con- 
 densed in the steam-pipes may usually be obtained 
 from the engineer. For laboratories not supplied 
 with steam or with running water, a " sanitary " still 
 is to be recommended. Information may be obtained 
 from A. R. Bailey Mfg. Co., 54 Maiden Lane, N. Y. 
 
 A water-bath may be constructed out of a pan 
 covered with a sheet-iron plate as shown in Fig. 24. 
 The small circles represent holes about two inches in 
 diameter for three-inch evaporators. The circle to 
 the right represents a disk about three inches in 
 diameter. Five of these should be provided for 
 covers. 
 
 The following list of chemicals is estimated on the 
 basis of ten students. As, however, it is not profitable 
 
126 APPENDIX. 
 
 * Glass plate, window-glass, 3" X 3* $0.05 
 
 Graduate, 50 cc. cylinder 23 
 
 * Leaden dish, 2" diam 08 
 
 Magnet, horseshoe, 2" 05 
 
 Magnif ying-glass, 1 glass, rubber case 37 
 
 Mortar and pestle, W. W., 4 oz 19 
 
 * Pincers, 4" 05 
 
 * Picture-wire, 6" No charge. 
 
 Platinum wire, 24 gauge, 3" > 24 
 
 Platinum-foil, med., Y X 1" 60 
 
 * Pneumatic trough, 5" X 1" X 10* 84 
 
 Reagent bottles, set of eight, 4 oz. : 
 
 Hydrochloric acid cone. 
 
 Hydrochloric acid dil. 
 
 Sulphuric acid cone. 
 
 Sulphuric acid dil. gg 
 
 Nitric acid cone. 
 
 Nitric acid dil. 
 
 Sodium hydrate. 
 
 Ammonia. 
 
 * Retort, 50 cc. with glass stopper , 20 
 
 * Eing-stand, w. 2 rings 34 
 
 * Test-tube rack for 6 tubes, w. pins 25 
 
 * Test-tubes, 16 X 160 mm., 1 doz 16 
 
 * Test-tube, one, 25 X 200 mm 03 
 
 * Thistle-tube, 14" 06 
 
 * Tube, rubber, J", 6 inches 05 
 
 * Tubes, soft glass, y i. d., 5 tubes 10 
 
 * Tube, hard glass, \" o. d 05 
 
 * Triangle for 1 J" crucible, pipe-stem 04 
 
 * Watch-glasses, \\" 05 
 
 Alcohol-lamp, 2 oz 12 
 
APPENDIX. 127 
 
 In addition to the apparatus just listed a number of 
 bottles of various sizes, and a few large beakers and 
 evaporating-dishes, should be included in the order. 
 These articles will be needed in making solutions 
 of reagents. 
 
 The laboratory should also be provided with a. 
 balance accurate to .05 grm., a set of weights, an 
 apparatus for distilling water, and a water-bath. 
 
 O 
 
 FIG. 24. 
 
 In case the building is heated by steam, water con- 
 densed in the steam-pipes may usually be obtained 
 from the engineer. For laboratories not supplied 
 with steam or with running water, a " sanitary " still 
 is to be recommended. Information may be obtained 
 from A. E. Bailey Mfg. Co., 54 Maiden Lane, N. Y. 
 
 A water-bath may be constructed out of a pan 
 covered with a sheet-iron plate as shown in Fig. 24. 
 The small circles represent holes about two inches in 
 diameter for three-inch evaporators. The circle to 
 the right represents a disk about three inches in 
 diameter. Five of these should be provided for 
 covers. 
 
 The following list of chemicals is estimated on the 
 basis of ten students. As, however, it is not profitable 
 
128 APPENDIX. 
 
 to purchase in too small quantities, many of the sub- 
 stances are listed in amounts sufficient for several 
 classes of this number. Items marked * are not in- 
 cluded in the estimate furnished by the supply house. 
 
 CHEMICALS. 
 
 Acetic Acid, No. 8, and bot., J Ib $0.07 
 
 * Alcohol. Procure revenue-free if used in quan- 
 
 tity. 
 
 Alum, potassium, J Ib . .12 
 
 Aluminium, foil, No. 34, 1 oz 06 
 
 Aluminium Sulphate, J Ib , 05 
 
 Ammonia, aqua, and bot., 5 Ibs 75 
 
 Ammonium Carbonate and bot., J Ib 11 
 
 Ammonium Chloride, gran., 2 Ibs 22 
 
 Ammonium Molybdate and bot., 1 oz 20 
 
 Ammonium Nitrate, ^ Ib 10 
 
 * Ammonium Sulphide. To be made in the labo- 
 
 ratory. 
 
 Animal Charcoal, gran., ^ Ib 10 
 
 Aniline Oil and bot., 1 oz 10 
 
 Antimony, powdered, 2 oz 05 
 
 Arsenic, metallic, 1 oz 05 
 
 Arsenic Trioxide, com., and bot., 1 oz 05 
 
 Barium Hydrate and bot., 2 oz , 18 
 
 Barium Chloride, in cart., J Ib 10 
 
 Benzene, C 6 H 6 , J Ib 15 
 
 Bleaching-powder, small can 09 
 
 Blue-print Paper, 4 X 5, 25 sheets, 1 pkge 15 
 
 Bone-ash, J Ib 05 
 
 Borax, 1 Ib 10 
 
 Bromine and 2 bots. and 2 cans, 2 oz 40 
 
 Beeswax, 2 oz 06 
 
 Cadmium, sticks and bot., J oz ,15 
 
APPENDIX. 129 
 
 Cadmium Chloride and bot., 1 oz $0.30 
 
 Calcium Carbide, 1 Ib 28 
 
 Calcium Chloride, gr., and bot., 1 Ib 26 
 
 Calcium Fluoride, powdered, 1 Ib 05 
 
 Calcium Hypophosphite, J Ib. in bot 42 
 
 * Calico, red. 
 
 * Candles. 
 
 Carbon Bisulphide and can, 1 Ib 19 
 
 Chalk, precipitated, Ib 07 
 
 Charcoal, 10 sticks 25 
 
 Chloroform and bot., J Ib .25 
 
 Chrome Alum, J Ib 05 
 
 Chromic Acid and bot., J Ib , 19 
 
 Cobaltous Chloride and bot., 1 oz 20 
 
 Cobaltous Nitrate and bot., 1 oz 52 
 
 Copper turnings, 1 Ib 35 
 
 Copper Oxide, powder, J Ib 25 
 
 Copper Sulphate, Ib. , 05 
 
 * Cotton, absorbent. 
 
 Ferric Chloride and bot., 2 oz 09 
 
 Ferrous Sulphate and bot., J Ib 08 
 
 Filter-paper, gray, 25 sheets, 12x17 18 
 
 Filter-paper, white, 11 cm. diam 13 
 
 * Gasoline. 
 
 Grape-sugar, commercial, 2 Ibs 19 
 
 Hydrochloric Acid and bot., 6 Ibs 85 
 
 Iceland Spar, 1 oz . 10 
 
 Indigo, 1 oz 07 
 
 Iodine and bot., f oz 20 
 
 Iron, reduced by hydrogen, J Ib 45 
 
 Iron, filings, 1 Ib 05 
 
 * Kerosene. 
 
 Lead foil, J Ib 10 
 
 Lead Acetate and bot., 2 oz , 20 
 
130 APPENDIX. 
 
 Lead Nitrate and bot., 2 oz $0.20 
 
 Lead Oxide, litharge, and bot., J Ib 15 
 
 Lead Oxide, minium, and bot., J Ib 18 
 
 * Lime. 
 
 Lithium Chloride and bot., -J oz 15 
 
 Litmus Paper, red and blue, large sheet, each ... .06 
 
 Magnesium ribbon, 5 ft 10 
 
 Magnesium Sulphate, J Ib 05 
 
 Magnesium Oxide and bot., J Ib . . , 40 
 
 Manganese Dioxide, 1 Ib 06 
 
 Manganous Sulphate and bot., J Ib 20 
 
 * Marble or limestone. 
 
 Mercury and bot., J Ib 24 
 
 Mercuric Chloride and bot., 2 oz 20 
 
 Mercuric Oxide and bot., 2 oz 30 
 
 Methyl Alcohol and bot, J Ib 10 
 
 Nickel Sulphate, J Ib 17 
 
 Nitric Acid and bot., 7 Ibs 1.02 
 
 Oxalic Acid, 1 Ib 13 
 
 Paraffine, 2 oz 05 
 
 Phosphorus, yellow, and bot. and can, 2 oz 38 
 
 Phosphorus, red, and bot., 2 oz . . . 45 
 
 Phosphoric Acid, ortho, and bot., 2 oz .......... .10 
 
 Potassium, metal, and bot. and can, 1 oz 1.70 
 
 Potassium Carbonate, dry, and bot., 2 oz 06 
 
 Potassium Bichromate, \ Ib 09 
 
 Potassium Bromide, \ Ib 18 
 
 Potassium Chromate, J Ib 15 
 
 Potassium Hydrate, sticks, pure by alcohol, 1 Ib., 
 
 and bot , 53 
 
 Potassium Ferrocyanide and bot., 1 oz .08 
 
 Potassium Ferricyanide and bot., 1 oz 10 
 
 Potassium Iodide and bot., J Ib 74 
 
 Potassium Permanganate, J Ib 19 
 
APPENDIX. 131 
 
 Kochelle Salt, J Ib $0.09 
 
 * Salt. 
 
 * Soap. 
 
 Silver Nitrate and bot., 1 oz 50 
 
 Sodium, metallic, and container, 1 oz 35 
 
 Sodium Bicarbonate, J Ib 05 
 
 Sodium Carbonate, dry powdered, J Ib 05 
 
 Sodium Carbonate, crystals, J Ib 05 
 
 Sodium Hydrate, sticks, pure by alcohol, 1 Ib., and 
 
 bot 50 
 
 Sodium Nitrate, coral., 1 Ib 11 
 
 Sodium Phosphate (di), J Ib 10 
 
 Sodium Silicate, water-glass, Ib., and bot 10 
 
 Sodium Sulphate, ^ Ib , . .05 
 
 Sodium Sulphide and bot., 1 oz 08 
 
 * Starch. 
 
 Strontium Chloride, J Ib t 10 
 
 * Sugar. 
 
 Sulphur, flowers, 1 Ib 05 
 
 Sulphur, roll, 1 Ib , 05 
 
 Sulphuric Acid, c. p., and bot., 9 Ibs 1.15 
 
 Tartaric Acid, \ Ib 23 
 
 Tartar Emetic and bot., 1 oz 08 
 
 Tin, granulated, 2 oz , 06 
 
 * Turpentine. 
 
 Toluidine (para), crystals, and bot., 1 oz 32 
 
 * Yeast. 
 
 Zinc, granulated, 2 Ibs 70 
 
 Zinc Oxide, by wet process, 2 oz 10 
 
 Except when specified chemicals are put up in paste- 
 board boxes. Bottles are furnished for all chemicals 
 at $2.00 extra. 
 
 The plan shown in Figs. 25 and 26 represents a 
 
132 
 
 APPENDIX. 
 
 Floor Pl< 
 
 32.X3Q- 
 
 Lecture tabl 
 
 :1 
 
 n 
 
 FIG. 25. 
 
APPENDIX. 
 
 133 
 
134 APPENDIX. 
 
 room 22' X 30' fitted with two work-tables 18' long, 
 38" high, and 30" wide. The lecture-table is 14' long, 
 33" high, 36" wide. The two cases for books, chemi- 
 cals, and apparatus are 5' long, 6^' high, and 18" deep, 
 with about four shelves to each case, glass doors in 
 front. The sink should be of enamelled iron or slate, 
 preferably the latter, though costing somewhat more, 
 size about 18" X 40", fastened to iron brackets on 
 wall or cased up below with wood. The following 
 material may be used for construction of cases, tables, 
 etc. : For framing 2" X 4" scantling ; doors in work- 
 tables and panels in lecture-tables f" yellow-pine 
 ceiling ; drawer-fronts, shelving, cases, casing, etc., |" 
 soft pine ; tops of work and lecture tables 1J" soft 
 pine. 
 
 A laboratory fitted as above described will cost from 
 $125.00 to $130.00, including varnish, etc. 
 
 The central part of the room has ample capacity for 
 seating. 
 
UNIVERSITY OF CALIFORNIA 
 
boo 7