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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.

901.

MnO4(aq) + 8H + 5Fe2+ 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

MnO4(aq) has a charge of 1

Let the oxidation number of Mn in MnO4(aq) be X

Recall, the oxidation number of O2 is 2

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

X - 8 = -1

X = +7

902.

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.

903.

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.

904.

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.

905.

Zn(s) + CuSO4(aq) \to ZnSO4(aq) + Cu(s)

In the reaction above, the oxidizing agent is

A.

CuSO4(aq)

B.

ZnSO4(aq)

C.

Cu(s)

D.

Zn(s)

Correct answer is A

No explanation has been provided for this answer.