WAEC Chemistry Past Questions & Answers - Page 48

236.

The periodic table is an arrangement of elements according to their?

A.

Oxidation number

B.

Atomic number

C.

Mass number

D.

Number of neutrons

Correct answer is B

Elements are arranged in order of increasing atomic number

237.

Which of the following is a physical change?

A.

Exposing white phosphorus to air

B.

Burning kerosene

C.

Dissolving calcium in water

D.

Freezing ice cream

Correct answer is D

No explanation has been provided for this answer.

238.

Which of the following will give a precipitate with an aqueous solution of copper (I) chloride?

A.

But-2-ene

B.

But-1-ene

C.

But-2-yne

D.

But-1-yne

Correct answer is D

No explanation has been provided for this answer.

239.

A secondary alkanol can be oxidized to give an?

A.

alkanone

B.

alkyne

C.

alkanoic acid

D.

alkanal

Correct answer is A

Secondary alkanols (alcohols) can be oxidised to alkanones (ketones)

240.

Petroleum is a non-renewable source of energy because it

A.

is formed naturally

B.

is cheap

C.

can be recycled after use

D.

cannot be regenerated once used up

Correct answer is D

No explanation has been provided for this answer.