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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    3. 0*341 gram of the silver salt of a tribasic acid left on heating 0*2151 gram of silver. Calculate the molecular weight of the acid. 4. Calculate the molecular weight of a mono-acid base from the following data: 0*3557 gram of the platinum salt gave o*i 17 gram of platinum. 5. What is the empirical formula of a compound having the following percentage composition : C = 23*58, H = 3*28, Cl = 23*23, N = 18*40, S = 21 *oo, O = 10*51 ? What precautions must be taken in the estima¬ tion of carbon and hydrogen in the above substance ? 6. Find the empirical formula of the substance of which the analysis is given in Question 7 on p. 25. 7. Calculate the molecular weight of grape-sugar determined by the cryoscopic method from the following data : 10 grams of substance dissolved in 73* 12 grams of water lowered the freezing-point i°*45. C = 18*8. 8. Describe Hofmann’s vapour density method. What are its advantages and disadvantages ? 9. Describe three distinct methods of arriving at the molecular weight of acetic acid. (B.E. Elem. 1900.) 10. Given a non-volatile, neutral, solid organic compound, how would you proceed to determine its molecular weight ? (B.E. Hons. 1899.) 11. Calculate the empirical formula of a compound having the composition, C — 85*71 per cent. ; II = 14*29 per cent. Describe the methods you would employ for the determination of the number of carbon and hydrogen atoms in the molecule of the substance in the event of its being (a) a gas, (b) a liquid, or (c) a solid. (B.E. Adv. 1891.) 12. The percentage composition of a liquid, containing carbon, hydrogen, and oxygen, was deduced from the following numbers 0*300 gram when submitted to combustion with copper oxide gave 0*574 gram of carbon dioxide and 0*351 gram of w*ater. The vapour density was 23 compared with hydrogen as unity. What is the formula of the liquid? (Univ. Coll. Lond. 1896.) 13. A monacid organic base, containing only hydrogen, nitrogen, and carbon, gave the following numbers on analysis :—0*186 gram gave 0*528 gram of carbon dioxide and 0*126 gram of water ; 0*596 gram of its platiniehloride yielded on ignition 0*195 gram of platinum. Calculate the molecular formula of the substance (Pt — 194*3). (Viet. B.Sc. 1901.)