WAEC Chemistry Past Questions & Answers - Page 75

371.

Which of the following gases will diffuse most rapidly?

[H = 1.00, C = 12.0, O = 16.0, S = 32.0, Cl = 35.5]

A.

Cl2

B.

SO2

C.

CH4

D.

C2H6

Correct answer is C

No explanation has been provided for this answer.

372.

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

Correct answer is C

No explanation has been provided for this answer.

373.

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

Correct answer is C

No explanation has been provided for this answer.

374.

Consider the following reaction equation:
SO42-(aq) + 2H+(aq) + ye- \(\to\) SO42-(aq) + H2O(1).

The value of y in the equation is

A.

2

B.

3

C.

4

D.

6

Correct answer is A

From the reaction, the total charge on the left side = The total charge on the right side

-2 + 2 + y = -2 : y = -2 : y = 2

375.

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

Correct answer is C

1 mole = Molar mass of gas = Avogadros number
32g of O2 = 6.02 x 1023
16g of O2 = x
x = \(\frac{16 \times 6.02 \times 10^23}{32}\) = 3.01 x 1023