Chemistry 1990 Waec Past Questions and Answers

Question 6 :

• WAEC 1990

The heat accompanying the reaction represented by the equation H₂O _(l) → H ₂O_(g) is described as the heat of

A. Solution
B. Neutralization
C. Vaporization
D. Sublimation
E. Activation

Question 7 :

• WAEC 1990

Aluminum is above iron in the electrochemical series, yet iron corrodes easily on exposure to air while aluminium does not. This is because aluminium

A. Has a lower density than iron
B. Is a better conductor than iron
C. Does not corrode spontaneously
D. Forms thin layer of inert oxide in moist air
E. Forms amphoteric oxides while iron does not

Question 8 :

• WAEC 1990

When a solid melts and consequently boils, there is

A. A gradual increase in the average kinetic energy of the particles
B. A sudden decrease in the kinetic energy of the particles
C. No change in the average kinetic energy of the particles
D. A rapid change in the nature of bonding of the com[onents
E. A change in the size of the fundamental particles

Question 9 :

• WAEC 1990

Which of the following compounds will undergo additional reactions?

A. Ethyne
B. Butane
C. Pentane
D. Tetrachloromethane
E. Ethanol

Question 10 :

• WAEC 1990

Which of the following reactions does not occur in the blast furnace during the extraction of iron?

A. Fe₂O_3(s) + 3CO_(g) → 2Fe_(l) + 3CO_2(g)
B. C₂ + CO _2(g)
C. CaO_(s) + SiO_2(s) → CaSiO _3(s)
D. FeO_(s) + CO_2(g) + Fe_(l)
E. 2Fe₂O_(s) → 4Fe_(l) 3O_2(g)