Separation of mixtures and purification of chemical substances - Jamb Chemistry Past Questions and Answers

Question 6:

• JAMB 1978

Which of the following gases may not be dried with concentrated sulphuric acid?

A. HCl
B. N₂
C. Cl₂
D. SO₂
E. NH₃

Question 7:

• JAMB 1978

The normal boiling point of a liquid is defined as

A. The temperature at which its vapour pressure equals the atmospheric pressure
B. The temperature at which bubbles begin to form
C. The temperature at which the vapour pressure equals 1 temperature
D. The temperature at which the rate of condensation of vapour equals the rate of vaporisation of the liquid
E. The temperature at which the space above the liquid is saturated

Question 8:

• JAMB 1978

Which of the following changes is physical?

A. Adding iron filing to aerated water
B. Adding sodium metal to water
C. Cooling a solution of Iron (II) sulphate to obtain the hydrated salt
D. Cooling water to obtain ice
E. Burning the domestic gas (Utilgas) for cooking

Question 9:

• JAMB 1978

By means of filtration, one component can be obtained pure from an aqueous mixture of sodium chloride and

A. Potassium nitrate
B. Sand
C. Lead nitrate
D. Sugar (glucose)
E. Starch

Question 10:

• JAMB 1979

When ammonium, potassium and calcium carbonates are each separately heated

A. None of them will decompose
B. Each of them will decompose to give carbondioxide and the respective oxide
C. Ammonium carbonate and potassium carbonate will not decompose
D. Only ammonium carbonate and the respective oxide
E. Ammonium carbonate will decompose to give carbondioxide, water and ammonia