WAEC Chemistry Past Questions & Answers - Page 266

1,326.

If a reaction is said to be exothermic, which of the following statements is a correct deduction from the information?

A.

the reaction vessel gets hotter as the reaction proceeds

B.

∆H for the reaction is positive

C.

the rate of the reaction increases with time

D.

the activation energy of the reaction is high

E.

the rate of the reaction increases with time

Correct answer is A

No explanation has been provided for this answer.

1,327.

Vulcanization of rubber

A.

stops the growth of fungus on the rubber

B.

increases the solubility of the rubber

C.

decreases the elasticity of the rubber

D.

hardnes the rubber through cross-linkage

E.

removes sulphur from the rubber

Correct answer is D

No explanation has been provided for this answer.

1,328.

The energy required to remove the most loosely bound electron from an atom in the gaseous state is known as the

A.

bond energy

B.

ionization energy

C.

potential energy

D.

activation energy

E.

kinetic energy

Correct answer is B

No explanation has been provided for this answer.

1,329.

Which of the following compounds is not correct about the reaction of sodium material for the manufacture of plastics?

A.

Ethyne

B.

Ethane

C.

Monochloroethene

D.

Propene

E.

Butadiene

Correct answer is B

No explanation has been provided for this answer.

1,330.

What is the number of oxygen atoms in 32g of the gas? (O = 16, L = 6.0 X 10\(^{23}\) mol\(^{-1}\))

A.

3.2 X 10 23

B.

6.0 X 1023

C.

1.2 X 1024

D.

1.6 X 1024

E.

2.0 X 1024

Correct answer is B

Oxygen is Diatomic

: 1 mole of oxygen contains 2 ATOMS

→ 2 X 16g = 32g

32g of the gas = 6.0 X 10\(^{23}\) mol\(^{-1}\)