Waec Chemistry 2008 Past Questions and Answers

Question 16:

• WAEC 2008

If 5.00cm³ of 0.20 mol dm^-3Na₂CO₃ was diluted with distilled water to obtain 250 cm³ solution, what is the concentration of the resulting solution?

A. 0.004 mol dm^-3
B. 0.02 mol dm^-3
C. 0.20mol dm^-3
D. 0.40mol dm^-3

Question 17:

• WAEC 2008

Consider the reaction represented by the following equation: Zn_(s) + 2HCI_(aq) → ZnCI_2(aq) + H_2(g) what volume of hydrogen gas is produced at s.t.p. when 3.25 g of zinc reacts with excess dilute HCI? [Zn = 65, Molar gas volume at s.t.p. = 22.4 dm^-3]

A. 1.12 dm³
B. 2.24dm³
C. 4.48dm³
D. 8.96dm³

Question 18:

• WAEC 2008

Which of the following gases has the lowerst rate of diffusion under the same conditions of temperature and pressure? [H = 1, O = 16, Ne = 20, CI = 35]

A. Chlorine
B. Hydrogen
C. Neon
D. Oxygen

Question 19:

• WAEC 2008

In a fixed volume of a gas, an increase in temperature results in an increase in pressure due to an increase in the

A. Number of the collisions between the gas molecules and the walls of the container
B. Kinetic energy of the gas
C. Number of collisions between the gas molecules
D. Number of repulsion between the gas molecules

Question 20:

• WAEC 2008

When concentrated H₂
SO ₄ is added to NaCI _(s), the gas evolved

A. Bleaches damp blue litmus paper
B. Forms a white preciptate with AgNO_3(aq)
C. Forms a white precipitate with BaCI_2(aq)
D. Turns moist red litmus paper blue