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.

1,291.

Which of the following pH values indicates that a solution is a strong base?

A.

1

B.

5

C.

9

D.

13

Correct answer is D

No explanation has been provided for this answer.

1,292.

On heating, the following trioxocarbonate (IV) salts decompose to give solid residue except

A.

ammonium trioxocarbonate (IV)

B.

calcium trioxocarbonate (IV)

C.

lead (ll) trioxocarbonate(IV)

D.

zinc trioxocarbonate (IV)

Correct answer is A

Ammonium trioxocarbonate (IV) is an unstable compound. It decomposes on heating to yield ammonia, carbon (IV) oxide and water. All of these are gases.

1,293.

A substance L reacts with NH\(_4\)NO\(_{3(aq)}\) to generate ammonia gas. L is likely to be

A.

HCl

B.

NaOH

C.

CH3COOH

D.

CaSO4

Correct answer is B

The reaction between NH\(_4\)NO\(_{3(aq)}\) and any metal hydroxide produces ammonia, water and an alkali metal nitrate.

1,294.

The energy evolved when magnesium burns in air is in the form of

A.

heat

B.

heat and sound

C.

light and heat

D.

sound

Correct answer is C

When a piece of magnesium ribbon is ignited, light and heat are produced.The reaction is an exothermic reaction, as well as one that produces light energy.

1,295.

Which of the following gases has the lowest rate of diffusion under the same condition? [H = 1.00; He = 4. 00; O = 16.0; CI = 35.5]

A.

CI2

B.

H2

C.

He

D.

O2

Correct answer is A

According to Graham's law of diffusion and effusion,

r \(\propto\) \(\sqrt{\frac{1}{M}}\).

Therefore, the more the molar mass, the less the rate of diffusion and effusion.