WAEC Chemistry Past Questions & Answers - Page 80

396.

The alkanol obtained from the production of soap is

A.

Dihydric Alkanol

B.

Tertiary Alkanol

C.

Trihydric Alkanol

D.

Monohydric Alkanol

Correct answer is C

No explanation has been provided for this answer.

397.

Which of the following metals is common to both brass and bronze?

A.

Aluminium

B.

Copper

C.

Lead

D.

Iron

Correct answer is B

No explanation has been provided for this answer.

398.

A consequences of global warming is

A.

Air pollution

B.

Flooding

C.

Increased humidity

D.

Water pollution

Correct answer is B

Global warming is a gradual increase in the earth’s temperature generally due to the greenhouse effect caused by increased levels of carbon dioxide,  CFCs, and other pollutants., consequences of global warming include: Seasonal/climate change, Rising oceans, Increase in flooding occurrences. Melting ice caps or polar ice. Increase in the average temperature of the world.

399.

Which of the following sources of energy contributes to green-house effect?

A.

Natural gas

B.

Nuclear

C.

Wind

D.

Solar

Correct answer is A

No explanation has been provided for this answer.

400.

Consider the following reaction equation
C2H4(g) + 3O2(g) \(\to\) 2CO2(g) + 2H2O(l).

The volume of oxygen at s.t.p that will be required to burn 14g of ethene is
[C2H4 = 28; Molar volume of gas at s.t.p = 22.4dm3

A.

64.2dm3

B.

33.6dm3

C.

11.2dm3

D.

3.73dm3

Correct answer is B

C2H4(g) + 3O2(g) \(\to\) 2CO2(g) + 2H2O(l)

1 mole of ethene required 3 moles of O2
28g of ethene required 3 x 22.4dm3 of O2

14g will require \(\frac{14 \times 3 \times 22.4dm^3}{28}\)

= 33.6dm3