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.

2,876.

2SO2(g) + O2(g) → 2SO3. In the reaction above, the standard heats of formation of SO2(g) and SO3(g) are -297 KJ mol-1 and -396 kJ/mol respectively. The heat change of the reaction is?

A.

-99 kJ mol-

B.

-198 kJ mol-

C.

+198 kJ mol-

D.

+683kJ mol-

Correct answer is B

2SO2 + O2 → 2SO3
2(-297) 2(-396)
-594 -792
Heat change = heat of product - heat of reactants = -792 - (-594) = -198kj mol-

2,878.

What is the oxidation number of Z in K3ZCl6?

A.

-3

B.

+3

C.

-6

D.

+6

Correct answer is B

No explanation has been provided for this answer.

2,879.

How many Faraday of electricity are required to deposit 0.20 mole of nickel, if 0.10 Faraday of electricity deposited 2.98g of nickel during electrolysis of its aqueous solution?

(Ni = 58.7, 1F = 96 500 C mol-)

A.

0.20

B.

0.30

C.

0.40

D.

0.50

Correct answer is C

No of mole → (2.98)/(58.7) ..............0.1

2.0 .................x
∴ x = (0.2)/(2.98) x 58.7 x 0.40

2,880.

When platinum electrodes are used during the electrolysis of copper (ll) tetraoxosulphate (lV) solution, the solution gets progressively?

A.

acidic

B.

basic

C.

neutral

D.

amphoteric

Correct answer is A

No explanation has been provided for this answer.