IQI5 



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. 



PART I 



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



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



receive credit, the equations must be absolutely correct. 



(a) Iron+hydrochloric acid = 



(b) Sodium chloride + sulphuric acid (cold) = 



(c) Nitric oxide +oxy gen = 



(d) Slaked lime+sulphur dioxide + water = 



(e) Sodium bicarbonate (heated) = 



(/") Barium chloride+ferric sulphate = 



2. (a) If the valence of A is two, derive the valences of B, C, and D from the 



following formulae: AB, A 3 C 2 , CD 3 , BD 2 . 



(b) Name the substances represented by the formulae FeBr 2 , FeBr 3 , H 2 S0 3 , 

 Na 2 SO 3 , Na 2 SO 4 , A1 2 S 3 O I2 . 



3. (a) Put into words all the information which is conveyed by the expression 



What factor of the change is not represented in this expression ? 

 (b) In what way does the atomic theory explain the law of definite propor- 

 tions ? 



(a) Give the sources and modes of preparation or purification of two of the 



following: (i) starch, (2) sugar, (3) carbon dioxide. 



(b) Describe tests involving chemical change sufficient for the identification 



of two of the following soluble salts: (i) a sulphate, (2) a sulphide, 

 (3) an ammonium salt. 



(c) Describe the method used for the preparation and isolation of two of the 



following substances. Write the equation for each reaction, (i) 

 potassium nitrate, (2) chlorine, (3) ethyl alcohol. 



(a) Calculate the weight of sulphur in 50 g. of Cr 2 (SO 4 ) 3 . Find the result to 



three significant figures. (Atomic weights Cr 52, S 32, O 16.) 



(b) How many liters of free oxygen measured under standard conditions may 



be obtained by heating 10 g. of potassium nitrate to give potassium 

 nitrite (KNO 2 ) ? (Weight of a liter of oxygen i . 43 g. Atomic weights 

 K 39, N 14.) 



(c) If 10 liters of air are passed into a closed space containing 100 liters of air 



at 760 mm. pressure, what change of pressure will be produced? 

 Assume the temperature to remain constant. 



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