WAEC Chemistry Past Questions & Answers - Page 158

786.

Aluminium is a good roofing material because it

A.

is strong and does not conduct heat and electricity

B.

readily absorbs light

C.

forms an oxide film over its surface which prevents corrosion

D.

is flexible and can conduct heat

Correct answer is C

The thin coat of aluminum oxide formed prevents further attack of the metal by atmospheric oxygen and water.

787.

Chemicals that are produced in small quantities and with very high degree of purity are

A.

bulk chemicals

B.

fine chemicals

C.

heavy chemicals

D.

light chemicals

Correct answer is B

No explanation has been provided for this answer.

788.

Which of the following substances causes the depletion of the ozone layer in the atmosphere?

A.

Carbon (IV) oxide

B.

Chlorofluorocarbon

C.

Sulphur (IV) oxide

D.

Hydrocarbons

Correct answer is B

No explanation has been provided for this answer.

790.

A hydrocarbon containing 88.9% carbon has the empirical formula [H = 1 C = 12]

A.

CH

B.

CH2

C.

C2H3

D.

C2H5

Correct answer is B

No explanation has been provided for this answer.