Solution. I. I vol. H unites with vol. Cl without condensation, producing, therefore, 2 vols. HCI, I Weight of 1 vol. H1 = 1 Weight of 2 vols. HCl = 36.5 ... Sp. gr. or weight of 1 vol. HCl=of 36.5=18.25. 2. 1 vol. O unites with 2 vols. H, condensing, so as to form, therefore, 2 vols. steam. 3. I vol. N and 3 vols. H unite and condense, so as to form 2 vols. NH3. 22. Describe the composition of the phosphates as illustrations of the salts of monobasic, bibasic, and tribasic acids. 23. Give an outline of the manufacture of sulphuric acid. 24. Give an outline of the manufacture of carbonate of soda. ORGANIC CHEMISTRY. GENERAL INSTRUCTIONS. Three hours are allowed for this paper. You are only permitted to attempt eight questions. You may select your questions from Series I., or from Series II., or from both. The value attached to the correct answer of each question in Series I. is 8; and those in Series II. is 12'5. N.B.-A full and exact answer will in all cases gain more marks than an inexact or incomplete answer; though in the former case the question may be the more easy of the two and have less marks attached to it. " SERIES I. 1. What is the composition of cyanogen, and how is 2. Describe the method of making hydrocyanic acid. 4. State the composition of marsh gas and the mode 5. State the composition of olefiant gas and the mode of preparing it. 6. What is meant by the term substitution? some examples of substitution. Give 7. What is meant by the term organic radical? Give some examples of organic radicals. 8. Give the names and formule of some of the simplest organic acids, 9. Give the names and formulæ of some of the simplest organic bases. 10. What becomes of oxalate of lime when it is heated? 11. What is soap? 12. State the nature of the green arsenical colour which is used in the manufacture of paperhangings. SERIES II. 13. Describe the process of alcoholic fermentation. 14. Describe the process of acetification. 15. Describe the process of etherification. 16. State the preparation, the composition, the properties, and the principal decompositions of oxalic acid. 17. Describe the method of preparing aniline. 18. Give some examples of alcohols homologous with ethylic alcohol, and also of the acids, hydrated and anhydrous, and of the ethers, simple, mixed, and compound, belonging to them. 19. Give some examples of organic bases, and explain the relation in which these substances stand to What is the formula of the compound? Give details of calculation. = 6 1 14 Solution. Divide the quantity of each element by its eq. These numbers show the proportion of the equivalents of the elements in the compound. They must now be reduced to whole numbers. To do this the easiest plan is to divide each number by the lowest number of equivalents expressed above, viz. 322 eqs. N. Dividing, then, by 3 22 we get The composition of the body is CH,N, and it may C2H2 be represented as HN, or methylamine. H ཝཱ 21. Describe the preparation of fulminate of mercury, and give the composition of this compound. 22. What is meant by the term isomerism? Give some example of isomerisin. 23. Describe the manufacture of prussiate of potash. 24. Give an outline of the process of saponification. QUESTIONS given at the Examination for Certificates in Chemistry, held at the South Kensington Museum, in November 1861. [Three hours allowed for this Paper.] INORGANIC CHEMISTRY. * SECTION I. 1. Describe the usual process for the preparation of chlorine.; 2. How is nickel separated from cobalt? 3. The formula usually adopted by chemists for felspar is KO,SiO,, + Alo, 3SiO. In this formula K=39, Al = 13'7, Si = 21, O= 8. What is the formula of felspar if the following equivalents be taken: K=39, Al=13'7, Si= 28,0=16? Solution. 169 Empirical formula of felspar = KAl, Si, O., which becomes (using the higher equivalent numbers for Si and O,) KAL, Si, O. Now, as potash, KO, and alumina, Al, O, become respectively KO and Al, O, it is very evident that the whole formula must be doubled, to do away with the half equivalents. It then stands thus, K, Al, Si, O. Again, the formula for silicic acid, SiO,, becomes Si O, and on removing the fractions, it will be seen that the Si and O are united (using the higher equivalents) in the proportion of 1 eq. of Si and 2 eqs. of O, or SiO. The formula K, Al, Si, O, may therefore be written KO, AIO, 6SiO, or K,O,3SiO, + (Al,)2O3,3 SiO2, the compound being regarded as a tersilicate of potash combined with the silicate of alumina. |