Ira Remsen.

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LIBRARY

OF THK

UNIVERSITY OF CALIFORNIA.

OIKT OK

SUMMER SCHOOL GLASS OF ../. W 6

Received

Accession No . (s-fls Class No.
DEPARTMEN'1 OF



mz^



m




CHEMICAL EXPERIMENTS



PREPARED TO ACCOMPANY REMSEN'S "INTRO-
DUCTION TO THE STUDY OF CHEMISTRY"



BY
IRA REMSEN

Professor of Chemistry in the Johns Hopkins University
AND

WYATT W. RANDALL

Associate in Ciiemistry in the Johns Hopkins University




NEW YORK
HENRY HOLT & COMPANY

1895



Copyright, 1895,

BY
HENRY HOLT & CO.



ROBERT DRUMMOND, ELECTROTYPBR AND PRINTER, NEW YORK.



PREFACE.

THIS book lias been prepared for use as a laboratory
guide to accompany the study of Remsen's " Intro-
duction to the Study of Chemistry." The experiments
included in the course are essentially those in the last
edition of the "Introduction." Minor changes have
been made in many of them ; essential changes in a
few. If the directions are followed, the average stu-
dent will experience no difficulty in carrying them out
successfully.

The numbering of the experiments in the " Intro-
duction" has been followed in this book; additional
experiments have been inserted, and designated as
" 15a," " 25a," " 256," etc. In the latter class will be
found a small number of experiments not contained in
the "Introduction," but which have been inserted
here in accordance with the recommendation of the
Committee on Secondary School Studies, whose report
was published by the United States Bureau of Edu-
cation in 1893. As many of the experiments there
recommended have been inserted as seemed to the
authors to be of advantage to the student following
this course, the time at disposal and the facilities of
the average laboratory being taken into account.

In some cases it may be that in laboratories not
completely equipped fairly satisfactory results may be
obtained with simpler apparatus. The effort has,
however, been made in this book to omit everything

iii



iv PREFACE.

which does not serve to insure the success of the ex-
perimental work.

It has seemed best to include all the experiments
contained in Eemsen's " Introduction to the Study of
Chemistry." There are, however, a number of these
which are not suited to general laboratory practice :
they should be reserved for the ]ecture-room, or at
most performed only with the assistance of a compe-
tent teacher. In this University the experiments in
the " Introduction " usually omitted from the general
laboratory course are Nos. 4, 25, 26, 28, 34, 43, 45,
47, 48, 56.

As many as possible of those omitted should be
performed by the teacher in the presence of the class ;
and the points of importance should be drawn out by
questions. Afterwards the pupils should write a full
account of what they have seen, and draw such con-
clusions as the experiments may lead to.

THE AUTHORS.
BALTIMORE, September, 1895.






LIST OP EXPERIMENTS.

1. Physical and chemical change.

2. Heat
3

4. The electric current and chemical change.

5. Manipulation of gases.

6. " " "

7. Mechanical mixture : recognition of ingredients.

8. " separation " "

Q K < ( It if

10. conversion by heat into a chemical com-

pound.

11. Contact and chemical change.
12.

13.
14.

15. " " " "
15a. Oxygen : from mercuric oxide.

16. " " potassium chlorate.

17. " " manganese dioxide.

18. " potassium chlorate and manganese dioxide.

19. Physical properties of oxygen.

20. Action of oxygen at ordinary temperature.

21. " " " on sulphur at high temperatures.

22. " " " " carbon " "

23. " " " " phosphorus ". "

24. " " " " steel at " "

25. Absorption of oxygen by iron at " "
25a. Oxidation in the air.

256. " " " "

26. Hydrogen: electrolysis of water.

27. " action of sodium on water.

28. " " " iron

29. " " '* zinc on acids.

30. Products of the action of zinc on acids.



vi LIST OF EXPERIMENTS.

31. Hydrogen: purification.

32. " physical properties.

33. " " "

34. " " "

35. burning in air.

36. does not support combustion.

37. Water included in porous substances.

38. " of crystallization.

39. " "

40. " "

41. Efflorescent compounds.

42. Deliquescent "

43. Water composed of oxygen and hydrogen.

44. " produced by the burning of hydrogen in air.

45. Electrolytic gas.

46. Action of hydrogen on hot copper oxide.

47. Oxyhydrogen blowpipe.

48. " " lime-light.

49. Distillation of water.
49a. Water as a solvent.

496. Solution with and without permanent chemical change.

49c. Solution aids chemical action.

49d r

50. Weight of oxygen in a given weight of potassium chlorate.

51. Atomic weight of zinc.

52. Action of sulphuric acid on salt.

53. Oxygen from manganese dioxide and sulphuric acid.

54. Chlorine.

55. Action of chlorine on compounds of hydrogen.

56. " "

57. Direct combination of chlorine and hydrogen.

58. Hydrochloric acid.

59. Preparation of potassium chlorate.

60. " *' bleaching-powder.

61. Neutralization : quantitative relations.

62. " formation of salts.

63. Air: proportion of oxygen.

64. " nitrogen.

65. " water-vapor.

66. " carbon dioxide.

67. " removal of carbon dioxide.



LIST OF EXPERIMENTS. VU

68. Air : formation of carbon dioxide.

69. " removal of water- vapor.

70. Ammonia.
71.

72. " acts as a base.

73. Direct combination of ammonia with volatile acids.

74. Nitric acid : preparation.

75. " " concentration.

76. " " as an oxidizing agent.

r*y tt t< <( a K <

78. " " " "

79. " "-', formation of nitrates

80. Action of nitrates under the influence of heat.

81. Solubility of nitrates in water.

82. Nitric acid reduced to ammonia.

83. Nitrous acid and nitrites.

84. Nitrous oxide.

85. Nitric oxide : preparation.

86. " " properties.
86#. " " analysis.

87. Carbon : use of bone-black for filters.

88. " direct union with oxygen.

89. " action upon metallic oxides.
90.

91. Carbon dioxide : formation in the lungs.

92. " " preparation from carbonates.

93. " '*,-' properties.

94. Formation of carbonates.
95.

96. Solution of calcium carbonate.

97. Carbon monoxide : preparation.

98. " " as a reducing agent.

99. Oxygen burning in an atmosphere of coal-gas.

100. Flame.

101. Reduction with the aid of the blowpipe.

102. Oxidation " '"

103. Bromine.

104. Action of sulphuric acid on bromides.

105. Iodine.

106. Solvents for iodine.

107. Iodine and starch.



LIST OF EXPERIMENTS.

108. Action of sulphuric acid on iodides.

109. Hydrofluoric acid.

110. Distillation of sulphur.

111. Crystallization of molten sulphur.

" sulphur from solution.

113. Direct union of sulphur and metals.

114. Hydrogen sulphide.

115. Insoluble sulphides.

116. Sulphur dioxide.

H7- " as a bleaching agent.

118. Reaction between phosphorus and iodine.

119. Phosphine.

120. Arsine.

121. Arsenic from arsine.

122. Action of carbon on arsenic trioxide.

123. Antimony and arsenic.

124. Stibine.

125. Antimony from stibine.

126. Bismuth.

127. Borax and boric acid.

128. Reactions of chlorides.

129. Preparation of hydroxides.

130. Reactions " "
131.

132. " " sulphides.

133. " nitrates.

134. Preparation of sulphates.
135.

136. Reactions " "

137. Reduction " "

138. Reactions of carbonates.

139. Preparation of silicates.

140. Silicic acid.

141. Potassium carbonate in wood-ashes.
141a. Action of potassium on water.

142. Potassium iodide.

143. Preparation of potassium hydroxide.

144. Nitre as an oxidizing agent.

145. Sodium carbonate : Solvay process,

146. Volatility of ammonium salts.

147. Ammonium sulphide.



LIST OF EXPERIMENTS. ix

148. Insoluble potassium salts.

149. Flame reactions.

150. Calcium chloride.

151. " hydroxide.
152.

153. Plaster of Paris.

154. Action of ammonium carbonate on calcium sulphate.

155. Calcium phosphate.

156. Zinc oxide.

157. Insoluble salts of zinc.

158. Precipitation of metallic copper.

159. Copper hydroxide.

160. Copper sulphide.

160&. Precipitation of mercury.

161. Analysis of coin-silver.

162. Halogen salts of silver.

163. Precipitation of metallic silver.

164. Insoluble salts of silver.
164$. Solvents for aluminium.

165. Aluminium hydroxide.

166. Alum.

167. Aluminium hydroxide precipitated by soluble carbonates.

168. " " ,.'" sulphides.

169. Precipitation of metallic lead.

170. Action of water and air on metallic lead.

171. Oxides of lead.

172. Lead peroxide as an oxidizing agent.

173. Action of sulphuric acid on lead peroxide.

174. Lead chloride.

175. Stannous chloride.

176. Stannic

177. Antimony and tin.

178. Analysis of solder.

179. " " bronze.

180. Ferrous and ferric hydroxides.

181. Potassium permanganate : preparation.

182. as an oxidizing agent.

183. " chromate.

184. " dichromate.

185. Conversion of dichromates into chromates.

186. Salts of chromic acid as oxidizing agents.



X LIST OF EXPERIMENTS.

187. Insoluble chromates.

188. Chromium as a base -forming element.

189. Fermentation of glucose.

190. Aldehyde.

191. Soap.

192. Hard water.
193.

194. Tannic acid.

How to analyze substances.

Examples for practice.

List of substances for examination.

195. Study of Class I.

196. " " " II.

197. " " " HI.: Aluminium.

198. " " " " Chromium.

199. " " " " Iron.

200. " " " " Zinc.

201. " " " " Manganese.

202. " " " "

203. " " IV.: Calcium.

204. " " " " Barium.

205. " " " V.: Magnesium.

206. '* " "VI.



Symbols and Atomic Weights of the Elements.
Weights and Measures.



CHEMICAL EXPERIMENTS.

GENERAL LABORATORY DIRECTIONS.

1. Neatness is one of the first conditions of success
in chemical work. Keep your laboratory desk, as well
as all your apparatus, clean.

2. Provide yourself with a working-apron to protect
your clothing.

3. Always have a decent towel available.

4. In observing use your own eyes.

5. In describing experiments use your own ivords.

6. In thinking over the results use your own mind.

1. An experiment should be repeated as many times
as may be necessary to secure accurate work.

8. If the results obtained are not those which you
have been led to expect, try in every way you can
think of to find out what the matter is. See first
whether you have worked exactly as directed.

9. After an experiment is finished, write in your
note-book in the laboratory an account of what you
have done. Remember that this account is not in-
tended to be a series of mere short-hand notes of your
work. Laboratory work, to be of value, must consist
of two parts : (1) the actual performance of certain
experiments, and (2) the preparation of a concise and
yet accurate record of the method employed and the
results obtained. If you are able to draw any con-

1



2 GENERAL LABORATORY DIRECTIONS.

elusions from what you have seen, state what these
conclusions are. Write the description accurately
and in as good English as possible. Do not use ab-
breviations. In referring to chemical substances do
not use simply the name, but the full name with the
symbol after it. Thus, potassium chlorate, KC1O 3 ;
hydrochloric acid, HC1. Further, in speaking of
chemical substances do not use symbols. For exam-
ple, do not say, " I poured some H 2 SO 4 into an H 2 O
solution of BaCl 2 ," but say in English what you did.

10. After you have written an account of an experi-
ment have it examined by the teacher before you go
on to the next one.

11. Always read before and after an experiment or
a set of experiments that part of the text-book in
which the experiment or experiments are referred to,
and keep reviewing constantly.

12. If an experiment not included in your course is
performed by you or by your teacher, write an accu-
rate account of it as if you had yourself performed it,
but do not make any statement without entirely satis-
factory reasons for making it.

13. In working with gases see that all the joints of
your apparatus are tight.

14. In case of fire, a moist towel thrown over the
flame will generally be sufficient to extinguish it.

15. Acid wounds should first be washed out, and a
paste of sodium bicarbonate and water then applied.

16. Burns should be treated with a paste of sodium
bicarbonate and water.



PHYSICAL CHANGE; CHEMICAL CHANGE. 3

PHYSICAL CHANGE; CHEMICAL CHANGE.
EXPERIMENT 1.

Platinum wire ; magnesium ribbon or wire.

1. Hold a piece of platinum wire in the flame of the
laboratory burner or of a spirit-lamp for a moment ;
then remove it and hold it in the air for a few ino
ments.

What kind of change did it undergo in the flame ?

2. Hold a piece of magnesium ribbon or wire in the
flame by means of a pair of pincers : what kind of
change takes place ? Give reasons for your conclu-
sions.

3. Mention some phenomena familiar to you that
further illustrate these two kinds of change.

HEAT AND CHEMICAL CHANGE.
EXPERIMENT 2.

Test-tube ; sugar.

In a clean dry test-tube put enough white sugar to
make a layer 4 to J inch thick. Holjl
the tube in the flame of a spirit-lamp
or of a laboratory burner as shown in
Fig. 1, until no further change takes
place. Meantime what have you no-
ticed?

What do you see on the sides of the
tube?

What is the color and taste of that
which remains behind ?

Does it dissolve in water ?

Is it sugar ? Fl -




4 ELECTRIC CURRENT AND CHEMICAL CHANGE.

EXPERIMENT 2 Continued.

Is the change which has taken place chemical or
physical ? Why do you think so ?
What caused the change ?

EXPERIMENT 3.

Arsenic-tube* ; mercuric oxide ; splinter of wood.

Into a clean, dry arsenic-tube put enough red oxide
of mercury (mercuric oxide) to fill the bulb three-
fourths full. Heat the tube as in Experiment 2.

What change in color takes place ?

What is deposited on the sides of the tube?

2. During the heating insert into the tube a splin-
ter of wood with a spark on the end. What follows?

Take it out and put it back a few times.
Is there any difference between the burning in the
tube and put of it ? What difference ?

3. Continue the heating until the red substance has
all disappeared.

How do you know that the red substance which you
put into the tube has been changed ?
Is the change chemical or physical ?
What caused the change ?

THE ELECTRIC CURRENT AND CHEMICAL
CHANGE.

EXPERIMENT 4.

2 cells of Grove or Bunsen type ; platinum-foil ; copper (or platinum)
wire ; sulphuric acid ; wood splinter ; apparatus shown in Fig. 2.

1. To the ends of the copper (or platinum) wires
connected with two cells of a Grove's or Bunsen's

* Such a tube is also called an ignition-tube or mattrass.



ELECTRIC CURRENT AND CHEMICAL CHANGE. 5



EXPERIMENT 4 Continued.

battery fasten small platinum plates, say 25 mm. (1
inch) long by 12 mm. (J- inch) wide. Insert these plat-
inum electrodes into water contained in a small shal-
low glass vessel about 15 cm. (6 inches) wide by 7 to 8
cm. (3 inches) deep, taking care to keep them separated
from one another. No action will take place, for the
reason, as has been shown, that water will not conduct
the current, and hence when the platinum electrodes
are kept apart there really is no current. By adding
to the water about one-tenth its own volume of strong
sulphuric acid we give it the power to convey the cur-
rent. It will then be observed that bubbles rise from
each of the platinum plates. In order to collect them
an apparatus like that shown in Fig. 2 may be used.

h and o represent glass tubes
which may conveniently be about
30 cm. (1 foot) long and 25 mm.
(1 inch) in internal diameter. They
are first filled with the water con-
taining one-tenth its volume of
sulphuric acid and are then placed
with the mouth under water in
the vessel A. The platinum elec-
trodes are now brought beneath
the inverted tubes. The bubbles
which rise from them will pass up-
ward in the tubes and the water
will be displaced. FlG 2

2. Gradually the water will be completely forced
out of one of the tubes, while the other is still half-full.
The substance thus collected in each tube is an in-
visible gas. After the first tube is full of gas, place




G



MANIPULATION OF GASES.



EXPERIMENT 4 Continued.

the thumb over its mouth and remove the tube. Turn
it mouth-upward and at once apply a lighted match
to it.

What takes place ? Was the gas in the tube ordi-
nary air? Does a tube full of air act in the same
way? Try it.

3. In the meantime the second tube will have be-
come filled with gas. Remove this tube in the same
way and insert a thin piece of wood with a spark on
it. What do you observe ? Is it air ? In what ex-
periment already performed have you observed some-
thing very like this ?

MANIPULATION OF GASES.
EXPERIMENT 5.

Pneumatic trough ; cylinder or test-tube.

1. Fill a glass cylinder or test-tube with water ;




FIG. 3.



close the mouth with a glass plate or with the thumb ;
invert the tube, and put the mouth under water in the



MECHANICAL MIXTURE. 7

EXPERIMENT 5 Continued.

trough. The water stays in the tube after the glass
plate or thumb is removed. Why ?

2. Now take a piece of glass or rubber tubing ; put
one end under the mouth of the inverted tube, and
blow gently through the other end. What happens ?
What becomes of the water which was in the tube ?
Why?

EXPERIMENT 6.

Pneumatic trough; cylinders or test-tubes.

Fill a cylinder or test-tube with water and invert it
in the trough, as in Experiment 5. Introduce a sec-
ond cylinder or test-tube,
full of air, mouth-downward
in the water in the trough ;
bring its mouth below that
of the first cylinder, and.
then incline it so that the
air passes from one vessel
to the other. See Fig. 4. FIG. 4.

Why does the air pass to the higher vessel? If the
second cylinder had been filled with an oil lighter
than water, could it have been transferred in the same
way?

MECHANICAL MIXTURE.
EXPERIMENT 7.

Powdered roll-sulphur; fine iron-filings; magnifying-glass or small
microscope.

Mix two or three grams of powdered roll-sulphur
and an equal weight of very fine iron-filings in a small
dry mortar. Examine a little of the mixture with a
microscope or a magnifying-glass.




8 MECHANICAL MIXTURE.

EXPERIMENT 7 Continued.

Can you distinguish the particles of sulphur and
those of iron ?

EXPERIMENT 8.

Mixture obtained in last Experiment; small magnet.
Pass a small magnet over the mixture.
Are particles of iron drawn out of the mixture ?
Has chemical action taken place between the sul-
phur and the iron-filings ? How do you know ?

EXPERIMENT 9.

Bisulphide of carbon ; powdered roll-sulphur ; dry test-tubes ; iron-
filings ; filter; good-sized watch-glass.

1. Pour two or three cubic centimeters of disulphide
of carbon * on about a gram of powdered roll-sulphur
in a dry test-tube and shake the tube.

Does the sulphur dissolve ?

2. In a second tube treat a little iron-filings in the
same way.

Does the iron dissolve ?

3. Now treat about half of the mixture prepared in
Experiment 7 with three or four times its bulk of
disulphide of carbon. After shaking thoroughly, pour
the contents of the test-tube upon a dry filter ; f catch

* Disulphide of carbon is a very volatile, inflammable liquid. In
working with it great care should be taken to keep it away from all
flames. You should never heat it, either for the purpose of aiding
solution or to evaporate it.

f A word about filters, before going further: If your filter-paper
is in the form of sheets, cut some of it into circular pieces of a
diameter about l times that of the funnel you intend to use it with.
Take one of these pieces, fold it twice, at right angles, so that it forms
a quadrant, open it out into a hollow cone and fit this into the fun-
nel. The funnel should be dry and clean. If the funnel is of the



MECHANICAL MIXTURE CONVERTED BY HEAT. 9

EXPERIMENT 9 Continued.

the filtrate upon a watch-glass. What is left in the
filter?

Is it iron ?

4. After the liquid has evaporated examine what is
left on the watch-glass.

Is it sulphur ?

A MECHANICAL MIXTURE CONVERTED INTO
A CHEMICAL COMPOUND BY HEAT.

EXPERIMENT 10.

Powdered roll- sulphur ; filings of wrought iron or powdered iron ;
dry test-tube; small dry mortar; magnifying-glass ; carbon
disulphide ; magnet ; dilute hydrochloric acid.

1. Mix three grams of finely-powdered roll-sulphur
with the same weight of fine iron-filings. Put the mix-
ture in a dry test-tube. Heat the bottom of the tube
strongly and note the changes. Does a glow spread
upwards through the contents of the tube ?

Is there any evidence that heat is caused by the
change ?

2. After the action is over and the tube has cooled
down, break it and put the contents in a small dry
m ortar.



right shape the paper will fit the walls close, with three thicknesses
of paper on one side and one on the other.

Now with the paper pressed down into place wet the filter with the
liquid which is to be filtered through it. As we generally work with
aqueous solutions, this will of course generally be water ; in Experi-
ment 9, however, carbon disulphide must be used. Once wet, the
paper will stay in place.

Two papers, one inside the other, will filter more rapidly and per-
fectly than one alone. A knowledge of this fact is often of value.



10 CONTACT AND CHEMICAL CHANGE.

EXPERIMENT 10 Continued.

Does the mass look like the mixture of sulphur and
iron with which you started?

3. Examine with a microscope or magnifying-glass ;
with carbon disulphide ; with a magnet.

Treat a little of the mass with dilute hydrochloric
acid and warm slightly. What takes place? Treat a
little of a mixture of iron and sulphur in the same
way. Is the action the same ? Are the products the
same?

Compare your observations with those made on the
mixture used in the preceding experiment.

What conclusions does this experiment lead you to ?

CONTACT AND CHEMICAL CHANGE.
EXPERIMENT 11.

Small piece of calc-sparor marble ; ignition-tube ; dilute hydrochloric
acid ; small porcelain evaporating- dish ; water-bath ; test-tube.

1. Examine a piece of calc-spar or of marble. No-
tice whether it is hard or soft. Heat a small piece in
a glass tube such as was used in Experiment 3.

Does it change in any way ?

Does it dissolve in water?

[In order to learn whether a substance is soluble in
water proceed as follows : Put a piece about the size
of a pea in a test-tube with distilled water. Thoroughly
shake, and then, as heating usually aids solution, boil.
Now pour off a few drops of the liquid on a piece of
platinum-foil or a watch-glass, and by gently heating
cause the water to pass off as steam. If there is any-
thing solid in solution there will be something solid



CONTACT AND CHEMICAL CHANGE. 11

EXPERIMENT 11 Continued.

left on the platinum-fail or watch-glass. If not, there
will be nothing left.]

2. Knowing now the general properties of the calc-
spar or marble you will be able to determine whether
it is changed or not. Treat a small piece with dilute
hydrochloric acid in a test-tube.

What takes place ?

3. After the action has continued for about half a
minute insert a lighted match in the upper part of the
tube.

Does the match continue to burn ?
Does the substance in the tube burn ?
Is the invisible substance in the upper part of the
tube ordinary air ?
How do you know ?
Does the solid substance disappear?

4. In order to tell whether it has been changed
chemically the hydrochloric acid must be got rid of.
This can be done by boiling

it, when it passes off in the
form of vapor, just as water
does, and then whatever is in
solution will remain behind.
For this purpose put the solu-
tion in a small, clean porcelain
evaporating-dish, and put this
on a vessel containing boiling
water, or a water-bath. The
operation should be carried

-, i -, FIG. 5.

on under a hood or, at any

rate, in a place where there is a good draught, so that

the vapors will not collect in the working room. They




12 CONTACT AND CHEMICAL CHANGE.

EXPERIMENT II Continued.

are not poisonous, but they are annoying. The ar-
rangement for evaporating is illustrated in Fig. 5.

5. After the liquid has evaporated and the substance
in the evaporating-dish is dry, examine it and carefully
compare its properties with those of the substance
which was put into the test-tube.

Is it the same substance ?

Is it hard or soft ?

Does it change when heated in an ignition-tube ?

Is there an appearance of bubbling when hydro-
chloric acid is poured on it ?

Does it dissolve in water ?

Does it change when allowed to lie in contact with
the air?

EXPERIMENT 12.

Test-tube ; bit of copper ; concentrated nitric acid ; evaporating-


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