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

Question 46:

• JAMB 1995

A liquid begins to boil when?

A. Its vapour pressure is equal to the vapour pressure of its solid at the given temperature
B. Molecules start escaping from its surface
C. Its vapour pressure equals the atmosphere pressure
D. Its volume is sightly increased

Question 47:

• JAMB 1997

A mixture of 0.20 mole of Ar, 0.20 mole of N₂ and 0.30 mole of He exerts a total pressure of 2.1 atm. The partial pressure of He in the mixture is?

A. 0.90 atm
B. 0.80 atm
C. 0.70 atm
D. 0.60 atm

Question 48:

• JAMB 1998

The addition of water to calcium oxide leads to?

A. A physical change
B. A chemical change
C. The formation of a mixture
D. An endothermic change

Question 49:

• JAMB 1998

The addition of water to calcium oxide leads to?

A. A physical change
B. A chemical change
C. The formation of a mixture
D. An endothermic change

Question 50:

• JAMB 1998

A mixture of iron and sulphur can be separated by dissolving the mixture in?

A. Steam
B. Dilute hydrochloric acid
C. Dilute sodium hydroxide
D. Benzene