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.

3,241.

Calculate the solubility in mol dm-3 of 40g of CuSO4 dissolved in 100g of water at 120°C?
[Cu = 64, S = 32, O = 16]

A.

4.00

B.

2.50

C.

0.40

D.

0.25

Correct answer is B

Solubility = \(\frac{\text{number of moles of solution}}{\text{vol of solution}}\)

100g of water = 100 cm\(^3\) = 0.1 dm\(^3\).

CuSO\(_4\) = 160 g/mol

No of moles of CuSO\(_4\) in 40g = \(\frac{40}{160}\)

= 0.25 mol.

Solubility = \(\frac{0.25}{0.1}\)

= 2.5 moldm\(^{-3}\).

3,242.

Substance employed as drying agents are usually?

A.

amphoteric

B.

hygroscopic

C.

efflorescent

D.

acidic

Correct answer is B

No explanation has been provided for this answer.

3,243.

Permanent hardness of water can be removed by?

A.

filtration

B.

adding slaked lime

C.

adding caustic soda

D.

boiling

Correct answer is C

-  this hardness cannot be removed by boiling. We can remove this hardness by treating the water with washing soda, caustic soda and permutit

3,244.

A noble gas with a high power of fog penetration used in aerodrome beacons is?

A.

krpton

B.

argon

C.

helium

D.

neon

Correct answer is D

No explanation has been provided for this answer.

3,245.

12D + 13T → 24He + 01n + energy
The reaction above illustrates?

A.

alpha decay

B.

artificial transmutation

C.

nuclear fussion

D.

nuclear fission

Correct answer is C

No explanation has been provided for this answer.