icia 

 CHEMISTRY 



Friday 3 .45-5. 45 p. m. 



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

 of the examination. 



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

 than eight questions. 



GROUP A. (Omit one question.) 



1. Describe a laboratory method, involving chemical change, by which you 

 could distinguish between: (a) a chloride and a carbonate, (b) nitrogen 

 and carbon dioxide, (c) a nitrate and a sulphate. 



2. What changes would take place if the following substances were left in an 

 open vessel: (a) sodium, (b) anhydrous calcium chloride, (c) lime-water, 

 (d) washing soda, (e) silver chloride, (/) concentrated sulphuric acid ? 



3. (a) What inferences of a chemical nature may be drawn in each case when a 



solid is heated in a narrow test-tube and behaves in one of the following 

 ways: (i) chars, (2) gives off water vapor, without charring, (3) gives 

 off carbon dioxide ? 



(b) How could you obtain : (i ) ammonia from ammonium sulphate, (2) chlorine 

 from zinc chloride, (3) sulphur dioxide from sulphuric acid ? 



4. (a) How should you show the presence of (i) carbon in impure manganese 



dioxide, (2) sand in impure sugar ? 



(b) How could you tell whether: (i) a solution is saturated, (2) water con- 

 tains dissolved air, (3) a salt is deliquescent, (4) a colorless sample of 

 water contains a dissolved solid ? 



GROUP B. (Omit either 6 or 7.) 



5. (a) Complete and balance the following equations using formulae throughout : 



(1) Barium chloride + sodium sulphate = 



(2) Sodium hydroxide-r-cupric nitrate = 



(3) Ferric chloride-f-sulphuric acid = 



(4) Sulphur dioxide + water -f- sodium hydroxide = 



(5) Sodium carbonate-f hydrochloric acid = 

 (b) Balance the following equations: 



(1) HN0 3 -H 2 0+NO+0 



(2) FeCL 2 +HCl+0-FeCL 3 +H 2 



6. (a) What relation exists between the molecular weights and the specific 



gravities of gases ? 



(b) Arrange the following in the order of increasing specific gravity: CH 4 , 

 CO, CO 2 , NH 3 , NO, N 2 O (atomic weights: C = 12, H= i, O = 16, N= 14). 



(c) Calculate the weight of one liter of any one of the gases mentioned in 

 6 (b). (One liter of hydrogen weighs o . 09 g.) 



7. (a) 3Fe+4H 2 O^Fe 3 4 +4H 2 . 



Explain why this is called a reversible reaction. Under what circum- 

 stances is all the iron converted into oxide of iron ? Under what cir- 

 cumstances is all the oxide reduced to iron ? 



(b) Give three examples of chemical changes, each producing a different 

 form of energy. 



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