I9I6 



Comprehensive Examination 



CHEMISTRY 



Friday, June 23 9:00 a.m.-i 2:00 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 Part I.) 



1. Discuss concisely the important classes of compounds — acids, bases, and 



salts — from the standpoint of: (a) their composition, (6) their prepara- 

 tion, (c) their properties. Illustrate your answer fully with formulas and 

 with equations for reactions. 



2. a) Give a concise statement of the constitution of matter according to the 



atomic theory. 

 b) State any two laws fundamental to the theory-, and show how this theory 

 explains these laws. 



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

 r The equations must be properly balanced to receive credit: 



a) Sodium acid carbonate+hydrochloric acid= ? 



b) Calcium phosphate+sulphuric acid (in excess) = ? 



c) Copper + nitric acid (dilute) = ? 



d) Ferric nitrate+ammonium hydroxide = ? 



e) SiUca-|- sodium carbonate (fused) = ? 



4. A certain quantity of magnesium dissolved in acid gave exactly 100 c.c. of 



dry hydrogen at a temperature of 22° C. and a pressure of 780 mm. How 

 many grams of metal were used ? Compute the result to three significant 

 figures (Mg=24.3). 

 Note. — A liter of hydrogen at o°C. and 760 mm. weighs 0.09 gm. 



5. Chlorine and nitric acid often act as oxidizing agents, sulphur dioxide and 



carbon as reducing agents. Explain these statements and give examples, 

 with equations, illustrating these actions. State any necessary conditions 

 of dilution or of temperature. 



Part II 

 SUPPLEMENTARY REQUIREMENTS 

 Group A 

 {Answer two questions from this group.) 



6. Give the names and formulas of five common minerals of industrial impor- 



tance. State what commercial use may be made of each of them. 



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