Processing math: 100%
Chemistry questions and answers

Chemistry Questions and Answers

Learn more about the properties, composition, and structure of substances (elements and compounds) with these Chemistry questions and answers. This Test can be used by students preparing for Chemistry in JAMB, WAEC, NECO or Post UTME.

186.

In the extraction of iron, hot air is introduced into the blast furnace through?

A.

valves

B.

open-hearths

C.

arcs

D.

tuyeres

Correct answer is D

Pre-heated air at about 600ºC is blown into the furnaces from the bottom through the tuyeres.

187.

Wrought iron is obtained by heating cast iron in a furnace with?

A.

magnetite

B.

haematite

C.

carbon(ii)oxide

D.

calcium trioxosilicate(iv)

Correct answer is B

Cast iron + haematite = wrought iron

188.

Electrons enter into orbitals in order of increasing energy as exemplified by?

A.

1S22S22PX22py22pz03s0

B.

1S22S22PX22py12pz13s0

C.

1S22S22PX12py12pz13s1

D.

1S22S22PX22py22pz03s1

Correct answer is B

Shells and subshells are filled in energy level order, so electrons will fill the 2p subshell before the 3s shell.

And the x subshell before the y and z.

189.

H+ + OH → H2O

The equation above illustrates

A.

precipitation

B.

hydration

C.

hydrolysis

D.

neutralization

Correct answer is D

A neutralization reaction is when an acid and a base react to form water and a salt and involves the combination of H+ ions and OH- ions to generate water.

190.

Which of the following best represent solid gas mixture?

A.

milk

B.

kerosene

C.

soil

D.

smoke

Correct answer is D

Solid in gas mixture: Smoke, ice clouds, dust.

Liquid in gas mixture: fog, mist, vapour and hair sprays.

Gas in solid mixture: aerogel, Styrofoam.