1916 

 CHEMISTRY 



Friday 9 : 00 a.m. Two hours 



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

 part of the examination. 



Answer nine questions as indicated below. No extra credit will be given for more 

 than nine questions. 



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



Part I 

 (Answer all questions in this group. Each question counts 12.) 



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



receive credit, the equations must be absolutely correct, 



(a) Silver nitrate+ ferric chloride = 



{h) Sodium carbonate+ nitric acid = 



(c) Ammonium chloride+ calcium hydroxide = 



{d) Zinc hydroxide+ hydrochloric acid = 



{e) Combustion of phosphorus in air = 



(/■) Silver chloride-f zinc= 



2. (a) Describe in detail how you should determine experimentally either 



(1) the hydrogen equivalent of some metal, or (2) the weight of a liter 

 of some gas. 

 {b) What is meant by the relative activity of the metallic elements ? Arrange 

 in order of decreasing activity the following: gold, hydrogen, zinc, 

 sodium, copper. (The arrangement must be correct throughout to 

 receive credit.) 



3. (a) Name each of the following compounds: the potassium salt of chlor- 



platinic acid, the sodium salt of tellurous acid, a compound containing 



magnesium and silicon only, the salt obtained by replacing half the 



hydrogen of carbonic acid with sodium. 

 {b) If the percentages of calcium in two samples of limestone are 40 per cent 



and 38 per cent respectively, what conclusion should you draw in 



regard to the specimens ? State the law upon which your conclusion 



is based. (Atomic weights: Ca 40, O 16, C 12.) 

 (c) A body of air at constant pressure occupies a volume of 500 c.c. at 20° C. 



At what temperature will its volume become 1,000 c.c. ? 



4. How should you proceed to produce the first-mentioned substance from the 



second in four of the following cases ? Describe each step in the process. 

 (a) Nitrogen from the atmosphere; 

 {b) Kerosene from crude petroleum; 

 (c) Sulphuric acid from sulphur; 

 {d) Lime water from marble; 

 (e) Hydrochloric acid from sulphuric acid. 



5. (a) How many grams of water of crystallization are there in the crystallized 



barium chloride (BaCl2 • 2H2O) obtained from 10 grams of barium ? 

 (Atomic weights: Ba 137, CI 35. 5, O 16, H 1.) 

 {b) How many cubic centimeters of ammonia gas, NH3, under standard 

 conditions, can be obtained from 5.00 grams of ammonium phos- 

 phate, (NH4)3P04, by treating it with sodium hydroxide in excess? 

 (NHj3P04+3NaOH = Na3PO,+3H20-}-3NH3. (Atomic weights: 

 P 31, Na 23, 10, N 14, H 1 .) One liter of ammonia weighs . 77 gram. 



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