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

Question 56:

• JAMB 2000

Sieving is a technique used to separate mixture containing solid particles of

A. Small sizes
B. Large sizes
C. Differents sizes
D. The same sizes

Question 57:

• JAMB 2000

50 cm³ of carbon (II) oxide was exploded with 150 cm³ of air containing 20% oxygen by volume. Which of the reactants was in excess?

A. Carbon (II) oxide
B. Carbon (IV) oxide
C. Oxygen
D. Nitrogen

Question 58:

• JAMB 2000

Which of the following types of bonding does not involve the formation of new substance?

A. Metallic
B. Covalent
C. Co-ordinate
D. Electrovalent

Question 59:

• JAMB 2001

Use the graph above to answer this question.How long does it take all the solid to melt?`

A. 2.5 mins
B. 6.0 mins
C. 1.0 min
D. 3.0 mins

Question 60:

• JAMB 2002

A little quantity of trichloromethane (b.pt 60,^oC) was added to a large quantity of ethanol (b.pt 78,^oC). The most probable boiling point of the resultant mixture is from

A. 69 ^oC - 70 ^oC
B. 70 ^oC – 74 ^oC
C. 82 ^oC – 84 ^oC
D. 60 ^oC – 78 ^oC