204. A gaseous mixture containing oxygen, nitrogen, and carbonic acid, yielded the following numbers on analysis. Calculate the proportion of the constituent gases in 100 volumes of the mixture (Bunsen) :—

205. Determine the amount of aqueous vapour in a sample of air which yielded the following numbers on analysis (Bunsen) :

206. Calculate the composition by volume of water

from the following eudiometric synthesis :

A. Hydrogen saturated with moisture.

B. Hydrogen + Oxygen saturated with moisture.
C. Residue after explosion saturated with moisture.

207. Find the volume of each constituent contained in one volume of methyl ether from the data below, and deduce its empirical formula :

209. A gaseous mixture collected from Hekla a month after an eruption yielded the following figures: find its percentage composition :

210. Find the percentage volume of H,SH2, CO2, N, CO, and CH present in a fumarolle-gas giving on analysis :

4

211. From the tabulated data, calculate the percentage amount of nitrogen present in each body analysed, and give the volumes, reduced to standard conditions, of the nitrogen and nitric oxide respectively in each case.

Measured in Frankland and Ward's apparatus.

212. Find the composition of marsh gas from the figures given below, obtained by Thomas's modification of Frankland and Ward's apparatus.

Temperature constant at 15.4° C.

Gas taken at 118.5 mm. pressure.

After addition of oxygen, pressure=357.8 mm.
Pressure after explosion=121°12 mm.

Pressure after absorption of CO2=2*32 mm.

213. Calculate the percentage of CO2 by volume contained in a sample of air which gave the accompanying data-10 c.c. of baryta solution agitated in a flask, containing the air, of 618 c.c. capacity, required 60 c.c. of normal oxalic acid for neutralization, of which I c.c. equals I c.c. of CO2 at o° C. and 760 mm.; bar. 726 mm., temp. 21° C. The same amount of baryta solution directly titrated with normal oxalic acid required 8.8 c.c.

214. To a solution of baryta sufficient alcoholic solution of phenolphthalein is added to produce a distinctly pink coloration; I c.c. of the solution=o'104 c.c. carbon dioxide. A volume of 25 c.c. of the coloured solution becomes decolorized on the aspiration of 540 c.c. of air through it, owing to the absorption of CO2; find percentage of CO2 present.

215. An analysis of a specimen of coal-gas is made by (1) successive absorption of carbon dioxide, ethylene (propylene, butylene), benzene, oxygen, and carbon monoxide by means of Hempel's pipettes; (2) combustion of the hydrogen in a palladium-asbestos tube; (3) combustion of the methane by red-hot copper oxide with estimation of the carbon dioxide produced by titration. From the subjoined figures find the composition by volume of the sample analysed :

Volume of gas employed

(1) Volume after absorption by KOH

Volume after treatment with Br water
Volume after treatment with fuming NO,H
Volume after alkaline pyrogallol absorption
Volume after treatment with cuprous

chloride .

99'I c.c.

97'7 c.c.

93'9 c.c.

92'9 c.c.

92'6 c.c.

86.5 c.c.

(2) Non-absorbable gas used for H estimation 40'6 c.c. Non-absorbable gas + air Volume after combustion.

99'0 c.c. 65'7 c.c.

(3) Residue of 657 c.c. is burned by air and copper oxide, and CO2 titrated by baryta-water and oxalic acid.

Gas measures 65'7 c.c. at 736 mm. and 20° C.
Baryta-water, I c.c.=I'04 c.c. oxalic acid=1'04 c.c.
methane.

216. 100 volumes of Manchester cannel gas contained 4'98 volumes of olefines, which yielded on combustion 1393 volumes of carbon dioxide. Required the volumes of ethylene (C, H1) and butylene (CH) contained in the gas, and the value of the illuminating power of the gas expressed in percentages of ethylene.

CALCULATION OF THE RESULTS OF
ATOMIC WEIGHT DETERMINATIONS.

The data required for these calculations, when not otherwise given, may be obtained from Table I. in the Appendix.

217. DUMAS found, on heating copper oxide in a stream of dry hydrogen, that a certain weight of this substance lost 59789 grams of oxygen, and yielded 67.282 grams of water. Calculate from these numbers the atomic weight of hydrogen.

218. Marignac obtained 314.894 grams of silver nitrate from 200 grams of silver. 14110 grams of silver nitrate required 6191 grams of potassium chloride for complete precipitation, and 10 339 grams of silver dissolved in nitric acid required 5120 grams of ammonium chloride for precipitation. Calculate the atomic weight of nitrogen from these data.