Chemistry 1999 Waec Past Questions and Answers

Question 16 :

• WAEC 1999

Exhaust fumes discharged from a smoky vehicle gradually become invisible as a result of

A. Diffusion
B. Combustion
C. Absorption
D. Emission

Question 17 :

• WAEC 1999

Which of the following movements can be described as random motion?

A. Wheelbarrow being pushed
B. Car travelling on a straight line
C. Gas molecules colliding in a flask
D. Planets going round the sun

Question 18 :

• WAEC 1999

Equal volumes of CO₂ cnd CO at s.t.p have the same

A. Mass
B. Density
C. Rate of diffusion
D. Number of molecules

Question 19 :

• WAEC 1999

Gas molecules are said to be perfectly elastic because

A. They collide without loss of energy
B. They move about in straight lines
C. The distances between them are negligible
D. The volume occupied by them is negligible

Question 20 :

• WAEC 1999

What volume of hydrogen is produced at s.t.p. When 2.60 g of zinc reacts with excess HCI according to the following equation? Zn_(s) + 2HCI_(aq) → ZnCI _2(aq) + H_2(g) [Zn = 65; 1 mole of a gas occupies 22.4dm³ at s.t.p]

A. 0.040dm ³
B. 0.896dm ³
C. 5.82dm ³
D. 8.62dm ³