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.

1,571.

If 60 cm3 of gas is heated from 27oC TO 50oC, what is the new volume of the gas at constant pressure?

A.

32.4cm 3

B.

55.7cm3

C.

64.6cm3

D.

111.1cm3

Correct answer is C

V1 = 60cm T1 = 273 +27 = 300K
T2 = 273 + 50 = 323KV2 = ?
V1/T1 = V2/T2 .: V2 = V1T 2/T1 = 60 x 323/300 = 19380/300 = 64.6cm3

1,572.

An orange drink concentrate is suspected to contain traces of poisonous green dye and a harmless dye having the same boiling point. Which of the following techniques is most suitable for isolating the dyes?

A.

Fractional distillation

B.

Paper chromatography

C.

Coagulation

D.

Recrystallization

Correct answer is B

No explanation has been provided for this answer.

1,573.

Which of the following factors that affect the rate of chemical reactions can be explained in terms of the collision theory? l. concentration ll. pressure lll. temperature lV catalyst

A.

l and ll only

B.

l, ll and lll only

C.

l and lll only

D.

l, II, lll and IV only

Correct answer is D

The factors that affect reaction rates are:

  • surface area of a solid reactant.
  • concentration or pressure of a reactant.
  • temperature.
  • nature of the reactants.
  • presence/absence of a catalyst

1,574.

WHICH OF THE FOLLOWING SALTS IS READILY SOLUBLE IN WATER?

A.

PbCI2

B.

Pb(NO 3) 2

C.

PbSO4

D.

PbCO 3

Correct answer is B

No explanation has been provided for this answer.

1,575.

What of the following pairs of acid and base will produce a solution with pH less than 7 at equivalence point?

A.

HNO3 and NaOH

B.

H2SO4 and KOH

C.

HCI and Mg(OH) 2

D.

HNO 3 and KOH

Correct answer is C

No explanation has been provided for this answer.