1918 



Comprehensive Examination 



CHEMISTRY 



Wednesday, June 19 2-5 p.m. 



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

 the examination imless the laboratory notebook is to be presented at a laboratory exami- 

 nation. 



Answer ten questions as indicated below. 



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



Part I 

 {Answer all questions in Part I.) 



1. Give (a) exact statement, (b) experimental proof, and (c) a practical applica- 



tion of one of the fundamental laws of chemistry. 



2. a) Outline three different methods for obtaining oxygen; give some idea of 



their relative cost. 



b) Write equations, using formulas, to show how each of three metals may be 

 obtained from ores or artilicial compounds. Each method involved 

 should be different from the others. 



3. a) Calculate the weight of manganese dioxide required to produce chlorine 



enough to fill a flask of 4 liters capacity when the barometer stands at 

 760 mm. and the temperature is 0° C. (Mn. =54.9, = 16, CI =35. 5.) 

 Note — A liter of chlorine at 0° C. and 760 mm. weighs 3.22 grams. 



b) What weight of manganese dioxide would be required if the flask were 

 filled at 760 mm. and 273° C. ? 



4. Give the formulas of two oxides of sulphur, one oxide of nitrogen, and one 



oxide of carbon, that are acid anhydrides. Show by equations how an 

 acid may be made from each of these, and give the name of the acid in each 

 case. 



5. Write equations for any five of the following reactions, using formulas through- 



out: (The equations must be properly balanced to receive credit.) 



a) Solid sodium nitrate heated with solid ammonium chloride = ? 



b) Hydrogen sulphide and ammonia = ? 



c) Phosphoric acid and aluminium hydroxide = ? 



d) Sodium iodide and chlorine = ? 



e) Zinc oxide heated with hydrogen sulphide = ? 



/) Sodium acid carbonate and calcium hydroxide = ? 



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