IQ14 



CHEMISTRY 



Saturday 9-11 a.m. 



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. 



GROUP A 

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



1. Write equations for six of the following reactions, using formulae throughout. 

 Equations must be absolutely correct to receive credit: 



(a) Zinc -f hydrochloric acid = 



(b) Calcium hydroxide + carbon dioxide = 



(c) Manganese dioxide + hydrochloric acid (cone.) = 



(d) Quicklime -f- water = 



(e) Calcium chloride + silver nitrate = 

 (/) Copper -f- nitric acid (dil.) = 



(g) Ferrous sulphide + hydrochloric acid = 



2. (a) Calculate the percentage of oxygen in the substance whose formula is 



Ca(N0 3 ) 2 . Find the result to three significant figures. (Atomic weights: 

 Ca 40, N 14, O 16.) 



(b) How many liters of oxygen would be necessary to burn twelve grams of 

 carbon to carbon dioxide ? The volume of oxygen is to be estimated at 

 standard conditions. (One liter of oxygen weighs i . 429 grams. Atomic 

 weight: C 12.) 



(c) What weight of silver chloride may be precipitated by silver nitrate from 

 one kilogram of sea-water containing 2 . 5 per cent of sodium chloride ? 

 (Atomic weights: Ag 108, Cl 35.5, Na 23.) 



3. Describe the method used by you in the laboratory in the preparation of two 



of the following substances; write the equation for the reaction, and tell 

 how each compound may be identified: (a) ammonia; (b) hydrogen 

 sulphide; (c) sulphur dioxide. 



4. (a) Give specific examples of chemical changes each of which results in the 



production of one of the following forms of energy: (i) heat; (2) light; 

 (3) electricity; (4) mechanical energy. 



(b) What is meant by the statement, "the atomic weight of sodium is 23" ? 



(c) Why does an iron wire burn rapidly in pure oxygen but not in the air ? 

 State the principle involved. 



(d) Define catalysis and give an example of catalytic action. 



