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.

2,566.

10.0 dm3 of water was added to 2.0 mol dm-3 of 2.5dm3 solution of HCl. What is the concentration of the final solution in mol dm-3?

A.

0.4

B.

8.0

C.

2.0

D.

0.5

Correct answer is A

C1V1 = C2V2

C2 = \(\frac{C_1V_1}{V_2}\)

= \(\frac{2.0 \times 2.5}{12.5}\)

= 0.4mol/dm-3

2,567.

In a water body, too much sewage leads to

A.

a decrease in the temperature of the water which cause in death of aquatic animals

B.

an increase in the number of aquatic animals in the water

C.

an increase in the bacterial population which reduces the level of oxygen in the water

D.

a decrease in the bacterial population which increases the level of oxygen in the water

Correct answer is C

No explanation has been provided for this answer.

2,568.

The solvent used for removing grease stain is

A.

turpentine

B.

ammonia solution

C.

ethanol

D.

solution of borax in water

Correct answer is B

No explanation has been provided for this answer.

2,569.

An example of a hygroscopic substance is

A.

CuO (S).

B.

MgCL2(S).

C.

CaCL2(S).

D.

NaOH(S).

Correct answer is A

No explanation has been provided for this answer.

2,570.

Steam changes the colour of anhydrous cobalt (ll) chloride from

A.

white to red

B.

blue to white

C.

blue to pink

D.

white to blue

Correct answer is C

No explanation has been provided for this answer.