Waec Chemistry 2015 Past Questions and Answers

Question 21:

• WAEC 2015

Consider the following reaction equation:
C₂H_4(g) + 3O_2(g) \(\to\) 2CO_2(g) + 2H₂O_(g)
The volume of CO2(g) produced at s.t.p when 0.05 moles of C₂H_4(g) was burnt in O_2(g) is
[Molar Volume of gas = 22.4dm³

A. 1.12dm³
B. 2.24dm³
C. 3.72dm³
D. 4.48dm³

Question 22:

• WAEC 2015

The number of oxygen molecules present in 16.0g of the gas is ______?
[Avogadro's number = 6.02 x 10²³]

A. 6.02 x 10²²
B. 6.02 x 10²³
C. 3.01 x 10²³
D. 1.51 x 10²³

Question 23:

• WAEC 2015

Consider the following reaction equation:
SO₄^2-_(aq) + 2H⁺_(aq) + ye^- \(\to\) SO₄^2-_(aq) + H₂O₍₁₎.
The value of y in the equation is

A. 2
B. 3
C. 4
D. 6

Question 24:

• WAEC 2015

The general gas equation was deprived from______?

A. Boyle's and Gay Lussac's laws
B. Boyle's and Graham's laws
C. Boyle's and Charles' laws
D. Dalton's atomic theory

Question 25:

• WAEC 2015

The vapour pressure of a liquid depends on:
I. Temperature II. rate of condensation III. Cohesive forces holding the particles together.

A. I
B. I and II
C. I and III
D. II and III