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

Question 41:

• JAMB 1994

A mixture of sand, ammonium chloride and sodium chloride is best separated by?

A. Sublimation followed by addition of water and filteration
B. Sublimation followed by addition of water and evaporation
C. Addition of water followed by filtration and sublimation
D. Addition of water followed by crystallization and sublimation

Question 42:

• JAMB 1994

A pure solid usually melts?

A. Over a wide range of temperature
B. Over a narrow range of temperature
C. At a lower temperature than the impure one
D. At the same temperature as the impure one

Question 43:

• JAMB 1995

Chromatography is used to separate components of mixtures which differ in their rates of?

A. Diffusion
B. Migration
C. Reaction
D. Sedimentaion

Question 44:

• JAMB 1995

Chromatography is used to separate components of mixtures which differ in their rates of?

A. Diffusion
B. Migration
C. Reaction
D. Sedimentaion

Question 45:

• JAMB 1995

Which of the following is a example of a chemical change?

A. Dissoultion of salt in water
B. Rusting of iron
C. Melting of ice
D. Separating a mixture by distillation