JAMB Chemistry Past Questions & Answers - Page 32

156.

Oxygen is absent in?

A.

Kerosene

B.

Soil

C.

Glass

D.

Cement

Correct answer is A

Kerosene contains hydrocarbon with twelve to eighteen carbon atoms per molecule

157.

The gas which causes global warming is?

A.

O\(_{2}\)

B.

CO\(_{2}\)

C.

N\(_{2}\)

D.

He

Correct answer is B

 Carbon dioxide, a colorless gas having a faint sharp odor and a sour taste. It is a greenhouse gas.

Global warming occurs when carbon dioxide (CO2) and other air pollutants collect in the atmosphere and absorb sunlight and solar radiation that have bounced off the earth’s surface. Normally this radiation would escape into space, but these pollutants, which can last for years to centuries in the atmosphere, trap the heat and cause the planet to get hotter. These heat-trapping pollutants—specifically carbon dioxide, methane, nitrous oxide, water vapor, and synthetic fluorinated gases—are known as greenhouse gases, and their impact is called GREENHOUSE EFFECT

158.

The atomic weight of nitrogen is?

A.

10

B.

12

C.

14

D.

16

Correct answer is C

Atomic weight, also called relative atomic mass, ratio of the average mass of a chemical element's atoms to some standard.

159.

Which of the following are chemical changes? 

I. cooking of food
II. digestion of food
III. freezing of water
IV. water is heated up

A.

I and II

B.

I, II, and III

C.

III and IV

D.

all of the above

Correct answer is A

No explanation has been provided for this answer.

160.

Which of the following is a non-metal that remains liquid at room temperature?

A.

Chlorine

B.

Phosphorus

C.

Bromine

D.

Helium

Correct answer is C

Bromine is a chemical element with the symbol Br and atomic number 35. It is the third-lightest halogen and is a volatile red-brown liquid at room temperature that evaporates readily to form a similarly coloured vapour.