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.

951.

Which of these metals CANNOT replace hydrogen from alkaline solutions?

A.

Aluminium

B.

Zinc

C.

Tin

D.

Iron

Correct answer is D

Aluminum, Zinc, and Tin react with both acids and alkalis to liberate hydrogen and so all are amphoteric metals except iron.

952.

MnO4(aq) + 8H + 5Fe2+ \(\to\) Mn2+(aq) + 5Fe3+(aq) + H2O. The oxidation number of maganese in the above reaction changed from

A.

+7 to +2

B.

+6 to +2

C.

+5 to +2

D.

+4 to +2

Correct answer is A

\(MnO_{{4}{(aq)}}\) has a charge of \(-1\)

Let the oxidation number of \(Mn\) in \(MnO_{{4}{(aq)}}\) be X

Recall, the oxidation number of \(O_{2}\) is \(-2\)

\(\therefore\) \(X + (-2\times 4) = -1\)

\(X - 8 = -1\)

\(X = +7\)

953.

If the relative atomic mass of an element is not a whole number, it can be deduced that the element is?

A.

Naturally radioactive

B.

abundant in nature

C.

a transition metal

D.

an isotopic mixture

Correct answer is D

No explanation has been provided for this answer.

954.

The principle of column chromatography is based on the ability of the constituents to

A.

move at different speeds in the column

B.

dissolve in each other in the column

C.

react with the solvent in the column

D.

react with each other in the column

Correct answer is A

No explanation has been provided for this answer.

955.

2SO2(g) + O2(g) \( \iff \)2SO3(g)

\( \bigtriangleup H = -395.7kJmol^{-1} \)

In the reaction above, the concentration of 2SO3(g) can be in creased by

A.

decreasing the pressure

B.

decreasing the temperature

C.

the addition of catalyst

D.

increasing the temperature

Correct answer is B

No explanation has been provided for this answer.