WAEC Chemistry Past Questions & Answers - Page 124

617.

Which of the following cells produce electrical energy from chemical reactions?
l. Lead-acid battery ll. Dry cell III. Deniell cell IV Electrolytic cell

A.

l and ll only

B.

l, ll, and III only

C.

lll and IV only

D.

I and III only

Correct answer is B

No explanation has been provided for this answer.

618.

Consider the reaction represented by the equation: N2O4(g) ⇌ 2NO2(g) ; ∆H = + x kJmol-1
What happens when the temperature is reduced at equilibrium?

A.

Concentration of N 2O4(g) decreases

B.

Concentration of N 2O4(g) increases.

C.

Pressure exerted by the gases increases

D.

Pressure exerted by the gases remains constant

Correct answer is B

No explanation has been provided for this answer.

619.

The following factors affect the solubility of a solid in a given solvent except

A.

nature of solute

B.

nature of solvent

C.

pressure

D.

temperature

Correct answer is C

No explanation has been provided for this answer.

620.

A substance is said to be impure if

A.

its melting point range is wide

B.

it dissolves in water with difficult

C.

it has a low melting point

D.

it is coloured

Correct answer is A

No explanation has been provided for this answer.