Jamb Chemistry 1982 Past Questions and Answers

Question 26:

• JAMB 1982

9.8g of solid potassium chlorate (KCIO₃) were added to 40 cm³ of water and heated to dissolve all the solid. As he solution cooled, crystals of potassium chlorate started forming at 60°C. The solubility of potassium chlorate at 66°C is therefore?

A. 24.5 mole per dm³
B. 0.2 mole per dm³
C. 10.0 mole per dm³
D. 20.0 mole per dm³
E. 2.0 mole per dm³

Question 27:

• JAMB 1982

100 cm³ of oxygen is made to react with 50 cm ³ of hydrogen, and the whole reaction mixture was then passed through anhydrous calcium chloride. What is the volume of gas left?

A. 5 cm³
B. 25 cm³
C. 50 cm³
D. 75 cm³
E. 100 cm³

Question 28:

• JAMB 1982

A mixture contains 20cm³ of hydrogen, 35cm³ of oxygen, 15cm³ of carbon monoxide and 10cm³ of nitrogen at S.T.P. Which of the following gives the mole fraction of hydrogen in this mixture?

A. 0.02
B. 0.16
C. 0.20
D. 0.25
E. 20

Question 29:

• JAMB 1982

0.07g of a hydride of carbon occupies 56.0cm³ at S.T.P. when vaporized and contains 14.29% by mass of hydrocarbon is(C = 12, H = 1)

A. CH₄
B. C₂H₂
C. C₂H₄
D. C₂H₆
E. C₃H₈

Question 30:

• JAMB 1982

The pressure on 100 cm³ of oxygen gas at 35°C is 750mm of Hg.What would be the volume of the gas if the pressure is increased to 1000mm of Hg without changing the temperature?

A. 133.3 cm³
B. 85 cm³
C. 75 cm³
D. 65 cm³
E. 58.3 cm³