Water - Jamb Chemistry Past Questions and Answers

Question 71:

• JAMB 2011

From the diagram above, find the amount of solute deposited when 200 cm\(^3\) of the solution is cooled from 55°C to 40°C.

A. 0.10 mole
B. 0.20mole
C. 0.01 mole
D. 0.02 mole

Question 72:

• JAMB 2011

The importance of sodium aluminate (III) in the treatment of water is to

A. Cause coagulation
B. Neutralize acidity
C. Prevent goitre and tooth decay
D. Kill germs

Question 73:

• JAMB 2011

Hardness of water is mainly due to the presence of

A. Calcium hydroxide or magnesium hydroxide
B. Calcium trioxocarbonate (IV) or calcium tetraoxosulphate (VI)
C. Sodium hydroxide or magnesium hydroxide
D. Calcium chloride or sodium chloride salts

Question 74:

• JAMB 2012

50 cm³ of gas was collected over water at 10^oC and 765 mm Hg. Calculate the volume of the gas at s.t.p. if the saturated vapour pressure of water at 10 ^oC is 5mm Hg

A. 49.19 cm ³
B. 48.87 cm ³
C. 48.55 cm ³
D. 48.23 cm ³

Question 75:

• JAMB 2012

The chemicals used to soften hard water involves the addition of

A. Insoluble sodium compounds which from soluble solutions of calcium and magesium
B. Solube soudium compounds which from soluble solutions of calcium and magnesium ions
C. Solube sodium compounds which from insoluble precipitates of calcium and magnesium ions
D. Insoluble precipitates of calcium and magnesium ions