Stoichiometry - Jamb Chemistry Past Questions and Answers

Question 36:

• JAMB 1987

The solubility of Na₃AsO₄(H₂O)₁₂ is 38.9g per 100g H₂O. What is the mass percentage of Na₃AsO₄ in the saturated solution?
(As = 75, Na = 23, O = 16, H = 1)

A. 87.27%
B. 38.9%
C. 19.1%
D. 13.7%

Question 37:

• JAMB 1988

The formula of a compound formed in a reaction between a trivalent metal M and a tetravalent non-metal X is~?

A. MX
B. M₃X₄
C. M₄X₃
D. M₃X₂

Question 38:

• JAMB 1989

The molar ratio of carbon to hydrogen of a volatile liquid compound is 1: 2. 0. 12 g of the liquid on evaporation at s.t.p. gave 32 cm³ of vapour. The molecular formula of the liquid is
[G.M.V =22.4 dm ³, C = 12, H = 1]

A. C ₃ H ₆
B. C ₄H ₈
C. C ₅C ₁₀
D. C ₆H ₁₂

Question 39:

• JAMB 1989

20.00 cm ³ of a solution containing 0.53 g of anhydrous Na₂CO₃ in 100 cm³ requires 25.00 cm³ of H₂SO₄ for complete neutralisation. The concentration of the acid solution in moles per dm is [H =1, C = 12, O = 16, Na =23, S = 32]

A. 0.02
B. 0.04
C. 0.06
D. 0.08

Question 40:

• JAMB 1989

Using 50 cm ³ of 1 M potassium hydroxide and 100cm ³ of 1 M tetraoxosulphate (VI) acid, calculate the respective volumes in cm ³ of base and acid that would be required to produce the maximum amount of potassium tetraoxosulphate (IV) [ = 39, S = 32, O = 16, H = 1]

A. 50, 50
B. 25, 50
C. 50, 25
D. 25, 25