Jamb Chemistry Past Questions For Year 1998

Question 26

30cm³ of hydrogen was collected over water at 27°C and 780 mm Hg. If the vapour pressure of water at the temperature of the experiment was 10 mm Hg, calculate the volume of the gas at 760 mm Hg and 7°C?

jamb 1998

• A. 40.0 cm³
• B. 35.7 cm³
• C. 28.4 cm³
• D. 25.2 cm³

Question 27

C₃H_8(g) + 50_2(g) → 4H₂O + 3CO_2(g). Form the equation above the volume of oxygen at s.t.p. required to burn 50cm³ of propane is?

jamb 1998

• A. 250 cm³
• B. 150 cm³
• C. 100 cm ³
• D. 50 cm³

Question 28

8.0 g of an element X react with an excess of copper (ll) tetraoxosulphate (lV) solution to deposit 21.3 g of copper. The correct equation for the reaction is?

(Cu = 64).

jamb 1998

• A. X_(s) + CuSO_4(aq) → Cu_(s) + XSO_4(aq)
• B. X_(s) + 2CuSO_4(aq) → 2Cu_(s) + X(SO₄)_2(aq)
• C. 2X_(s) + CuSO_4(aq) → Cu_(s) + X₂SO_4(aq)
• D. 2X_(s) + 3CuSO_4(aq) → 3Cu_(s) + X₂(SO₄)_3(aq)

Question 29

A given amount of gas occupies 10.0 dm³ at atm, and 273°C. The number of moles of the gas present is?

(Molar volume of a gas at s.t.p. = 22.4 dm³)

jamb 1998

• A. 0.89 mol
• B. 1.90 mol
• C. 3.80 mol
• D. 5.70 mol

Question 30

Potassium tetraoxomanganate (VII) is often added to impure water to?

jamb 1998

• A. reduce organic impurities
• B. reduce inorganic impurities
• C. destroy bacteria and algae
• D. remove permanent hardness