Stoichiometry - Jamb Chemistry Past Questions and Answers

Question 61:

• JAMB 1995

The number of hydrogen ions in 4.9 g of tetraoxosulphate (IV) acid is?
(S = 32, O =16, H = 1, Na = 6.02 x 10₂₃

A. 3.01 x 10₂₂
B. 6.02 x 10₂₂
C. 3.01 x 10₂₃
D. 6.01 x 10₂₃

Question 62:

• JAMB 1995

What volume of oxygen will remain after reacting 8cm³ of hydrogen with 20cm³ of oxygen?

A. 10 cm³
B. 12 cm³
C. 14 cm³
D. 16 cm³

Question 63:

• JAMB 1997

An element, X, forms a volatile hydride XH₃ with a vapour density of 17.0. The relative atomic mass of X is?
(H = 1)

A. 34.0
B. 31.0
C. 20.0
D. 14.0

Question 64:

• JAMB 1997

A sample of a substance containing only C and H burns in excess O₂ to yield 4.4g of CO₂
and 2.7 g of H₂O. The empirical formula of a substance is?
(C = 12, O = 16, H = 1)

A. CH₃
B. CH₂
C. CH₄
D. C₂H₂₄

Question 65:

• JAMB 1998

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)

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