1917 

 Comprehensive Examination 



CHEMISTRY 



Friday, June 22 2-5 p.m, 



A teacher's certificate covering the laboratory instruction must be presented as a part 

 of the examination unless the laboratory notebook is to be presented at a laboratory 

 examination. 



Answer ten questions as indicated below. 



Attach to the answer, in each case, the number and letter used in the printed paper. 



Part I 

 (Answer all questions in Pari I.) 



1. a) Name and define four different types of chemical action, and illustrate 



each by an experiment which you have performed in the laboratory, 

 stating the object of the experiment, together with the names of the 

 substances used and of the products formed. 

 b) What is meant by a radical ? Give an example to show how a radical may 

 be decomposed in a chemical change. 



2. c) State the Law of Multiple Proportions, and illustrate it by the considera- 



tion of two compounds of carbon and hydrogen containing respectively 

 75 per cent and 92 . 3 per cent of carbon. 

 b) How does this law support the hypothesis that the elements are composed 

 of atoms having def-nite weights ? 



3. a) How many grams of hydrochloric acid gas can be obtained by heating ten 



grams of crystallized ferric chloride, FeCl3'6H20, with concentrated 

 sulphuric acid? (H = l, = 16, CI =35. 5, Fe = 56.) 



b) What is the percentage of sulphur in iron alum, K2S04-Fe2 (804)3 •.24H2O ? 

 (K=39, S=32, = 16, Fe = 56, H = l.) 



4. Give a detailed account of a good laboratory method for preparing and 



collecting chlorine in quantity; write the chemical equations involved; 

 make a diagram of the apparatus. 



5. Write equations for the following reactions, using formulas throughout. 



The equations must be properly balanced to receive credit. 



a) Calcium hydroxide and sulphurous acid = ? 



b) Steam and magnesium (heated) = ? 



c) Hydrogen sulphide burned in excess of oxygen = ? 



d) Nitric acid and ammonia gas= ? 



e) Aluminium sulphate and ammonium hydroxide = ? 



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