Pagel 



1920 



CHEMISTRY 



Monday, September 20 2-5 p.m. 



Answer ten questions as indicated below. 



Number and letter your answers to correspond to the questions selected. 



Part I 

 (Answer all questions in Part I.) 



1. Write equations for the following reactions, using formulas throughout. The 



equations must be properly balanced to receive credit. 



a) Nitric acid on ammonium carbonate = 



h) Silver nitrate solution and magnesium chloride solution = 



c) Hydrochloric acid and oxygen (with a catalytic agent) = 



d) Calcium phosphate and sulphuric acid = 



e) Hydrogen sulphide on lead nitrate solution = 



2. a) What particular properties are used in recovering the sulphur from a solu- 



tion in carbon disulphide ? 

 h) What chemical tests are used in recognizing sulphuric acid ? a chloride ? 

 nitrous oxide ? 



3. a) Fifty cubic centimeters of a solution containing 40 grams of sodium 



hydroxide per liter neutralize 40 cc. of a solution of hydrochloric acid. 

 WTiat is the concentration of the acid solution in grams per hter? 

 (CI 35.5, Na 23, O 16, H 1.) 

 h) How many grams of potash alum (K2S04'Al2(S04)3*24 H2O) can be made 

 from 69 grams of bauxite (AI2O3 • 2 H2O) ? (K 39, S 32, Al 27, 16, H 1.) 



4. Carbon dioxide gas in excess is passed into a water solution of sodium carbonate. 



Write an equation to express the chemical change which takes place. The 

 resulting solution is boiled vigorously for some time. Write an equation 

 to represent the reaction and name the substance which is left in the solu- 

 tion. Explain why these reactions proceed in opposite directions. 



5. a) WTiy is sulphuric rather than hydrochloric acid used in making nitric acid ? 



b) Why is hydrochloric rather than nitric acid used in making hydrogen 



sulphide ? 



c) Why is hydrochloric rather than sulphuric acid used in making carbon 



dioxide from marble ? 



d) Why is sulphuric rather than hydrochloric acid used in preparing oxygen 



from water by electrolysis ? 



e) Why is nitric rather than hydrochloric acid used to dissolve a silver coin ? 

 /) Why is dilute rather than concentrated sulphuric acid used in making 



hydrogen ? 



(THIS EXAMINATION IS CONTINUED ON PAGE 2) 



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