Stoichiometry - Jamb Chemistry Past Questions and Answers

Question 76:

• JAMB 2002

A compound contains 31.91% potassium, 28.93% chlorine and the rest oxygen. What is the chemical formula of the compound?
[K = 39, Cl = 35.5, O = 16]

A. KClO₄
B. KClO
C. KClO₂
D. KClO₃

Question 77:

• JAMB 2003

What volume of oxygen is produced from the decomposition of 2 mole of KCIO₃ at s.t.p?
[Molar volume of a gas at s.t.p = 22.4 dm³]

A. 22.4 dm³
B. 33.6 dm³
C. 44.8 dm³
D. 67.2 dm³

Question 78:

• JAMB 2003

What volume of oxygen is produced from the decomposition of 2 mole of KCIO₃ at s.t.p?
[Molar volume of a gas at s.t.p = 22.4 dm³]

A. 22.4 dm³
B. 33.6 dm³
C. 44.8 dm³
D. 67.2 dm³

Question 79:

• JAMB 2003

What is the percentage by mass of oxygen in Al₂(SO₄)₃. 2H₂O?
[Al = 27, S = 32, H = 1, O = 16]

A. 14.29%
B. 25.39%
C. 50.79%
D. 59.25%

Question 80:

• JAMB 2003

What mass of K₂CrO₄ is required to prepare 250cm³ of 0.020 mol dm³ solution?
[K₂CrO₄ = 194.2g mol^-1]

A. 0.97g
B. 9.70g
C. 19.42g
D. 97.10g