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.

2,516.

A piece of filter paper moistened with lead (ll) ethanoate solution turns black when the paper is dropped into a gas likely to be

A.

sulphur (VI) oxide

B.

hydrogen chloride

C.

sulphur (VI) oxide

D.

hydrogen sulphide

Correct answer is D

No explanation has been provided for this answer.

2,517.

The highest rate of production of carbon (lV) oxide can be achieved using

A.

0.05 mol -3HCI and 5g powdered CaCO3

B.

0.05 mol -3HCI and 5g lump CaCO3

C.

0.10 mol -3HCI and 5g powdered CaCO3

D.

0.025 mol -3HCI and 5g powdered CaCO3

Correct answer is C

No explanation has been provided for this answer.

2,518.

An increase in entropy can best be illustrated by

A.

mixing of gases

B.

freezing of water

C.

the condensation of vapour

D.

solidifying candle wax

Correct answer is A

No explanation has been provided for this answer.

2,519.

CO(g) + H\(_2\) O\(_{(g)}\) → CO\(_{2(g)}\) + H\(_{2(g)}\)
Calculate the standard heat change of the reaction above, if the standard enthalpies of formation of CO\(_{2(g)}\), H\(_2\)O\(_{(g)}\) and CO\(_{(g)}\) in kJmol\(^{-1}\) are - 394, -242 and - 110 respectively.

A.

+ 262 KJ mol -1

B.

- 262 KJ mol -1

C.

+ 42 KJ mol -1

D.

- 42 KJ mol -1

Correct answer is D

\(\Delta H (formation) (CO_2) = -394\)

\(\Delta H (formation) (H_2 O) = -242\)

\(\Delta H (formation) (CO) = -110\)

\(X = \sum H_{P} ^{F} - \sum H_{R} ^{F}\)

= (-394+ 0) - (-110 - 242 )

= -394 +352

= - 42 kJmol\(^{-1}\)

2,520.

A metal M displaces zinc from ZnCl solution
This shows that

A.

electrons flow from zinc to M

B.

M is more electropositive than zinc

C.

M is more electonegative than zinc

D.

zinc is more electropositive than M

Correct answer is B

No explanation has been provided for this answer.