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.

3,716.

50 cm3 of carbon (II) oxide was exploded with 150 cm3 of air containing 20% oxygen by volume. Which of the reactants was in excess?

A.

Carbon (II) oxide

B.

Carbon (IV) oxide

C.

Oxygen

D.

Nitrogen

Correct answer is C

2CO + O2 → 2CO2
50cm3 → 25cm3
20% * 150 = 30cm3
30 cm3 is the volume of oxygen available for the reactions. But only 25 cm3 is required; therefore O2 is in excess

3,717.

Which of the following compounds is composed of Al, Si, O and H?

A.

Epsom salt

B.

Limestone

C.

Clay

D.

Urea

Correct answer is C

Clay is Alumina silicate and the formula is AL2O3 2SiO2 2H2O

3,718.

Sieving is a technique used to separate mixture containing solid particles of

A.

small sizes

B.

large sizes

C.

differents sizes

D.

the same sizes

Correct answer is C

No explanation has been provided for this answer.

3,719.

A mixture of iodine and sulphur crystals can be separated by treatment with?

A.

Water to filter off sulphur

B.

carbon (IV) sulphide to filter off iodine

C.

ethanoic acid to filter off sulphur

D.

methanol to filter off iodine

Correct answer is B

A mixture of iodine and sulphur can be separated by adding Carbon disulphide that is (CS₂) then stir the solution and filter it . As sulphur dissolved in CS₂, so it come into filter and got separated from the mixture.

3,720.

When the two end alkyl groups ethyl ethanoate are interchange, the compound formed is known as

A.

methyl ethanoate

B.

ethyl propanaote

C.

methyl propanoate

D.

propyl ethanoate

Correct answer is C

No explanation has been provided for this answer.