Theoretical organic chemistry / by Julius B. Cohen.

Julius B. Cohen

Date:: 1902

Catalogue details

Licence: Public Domain Mark

Credit: Theoretical organic chemistry / by Julius B. Cohen. Source: Wellcome Collection.

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being filled in with the mixture of sodium carbonate and lime. The crucibles are heated over the blow-pipe, the contents allowed to cool, and dissolved in excess of dilute nitric acid. The halogen is then precipitated with silver nitrate and estimated in the usual way. Example.—0*151 gram of substance gave o’134 gram AgBr. •134 x 80 x 100 --= 37* s 1 per cent, ot bromine. 188 x ’151 a/ d x Sulphur.—Carius’Method.—The process is essentially the same as that just described. The compound is oxidised in a sealed tube-Avith fuming nitric acid, but without the addition of silver filtrate. The resulting sulphuric acid is then precipitated and’ weighed as barium sulphate. Example.—o’2518 gram gave o’2638 gram BaS04. •2638 x 32 x 100 ~ . —x-x-= 14-30 per cent, of sulphur. 233 x ’2518 Questions on Chapter II 1. How would you show that alcohol contains carbon, hydrogen, and oxygen? 2. Calculate the percentage composition of cane-sugar, C12H22On. 3. Describe and explain the difference in the method employed in the estimation of chlorine in chloroform and calcium chloride. 4. Calculate the weight of carbon dioxide and water, and the volume of nitrogen under normal conditions, obtainable from o-2 gram of urea, ch4n2o. 5. Describe a method for the estimation of nitrogen in organic compounds. 6. Calculate the percentage of nitrogen estimated by Kjeldahl s method from the following data : 0 5 gram of the substance was decom¬ posed and distilled with caustic soda, and the ammonia collected in 50 c.c. of normal sulphuric acid. The acid then required 33 6 c.c. of normal caustic soda solution for neutralisation. 7. Calculate the percentage of carbon, hydrogen, and oxygen from the following data : 0’2046 gram of substance gave, on combustion, 0^2985 gram of carbon dioxide and OU255 gram of water.