Waec Chemistry 1990 Past Questions and Answers

Question 26:

• WAEC 1990

To what temperature must a gas be raised from 273K in order to double both its volume and pressure?``

A. 298k
B. 300k
C. 546k
D. 819k
E. 1092k

Question 27:

• WAEC 1990

Which of the following explains why trioxonitrate (V) acid is not used for preparing hydrogen from metals?

A. It is volatile
B. It is strongly oxidizing
C. It forms a layer of oxide on the metal
D. Trioxonitrate (V) salts are soluble in water
E. It renders the metals passive

Question 28:

• WAEC 1990

Which of the following is normally used for drying ammonia gas?

A. Concentrated tetraoxonitrate (Vl) acid
B. Calcium oxide
C. Anhydrous calcium chloride
D. Phosphorus (V) oxide
E. Anhydrous copper (ll) tetraoxosulphate (VI)

Question 29:

• WAEC 1990

Nuclear reactions can be used in the following except

A. Gauging the thickness of objects
B. Making atomic bombs
C. Curing cancer
D. Generating electricity
E. Purifying water

Question 30:

• WAEC 1990

The decomposition of hydrogen peroxide is represented by the equation: 2H₂O_(l) + O_2(g) what mass of hydrogen peroxide would be required to produce 22.4dm₃ of oxygen at s.t.p? (H = 1, O = 16, molar volume of a gas at s.t.p. = 22.4dm₃)

A. 18 g
B. 34 g
C. 36 g
D. 64 g
E. 68 g