Chemical combination - Jamb Chemistry Past Questions and Answers

Question 106:

• JAMB 2004

What volume of gas is evolved at S.t.p if 2g of calcium trioxocarbonate (IV) is added to a solution of hydrochloric acid?
[Ca = 40, C = 12, O = 16, Cl = 35.5, H = 1 Molar volume of agas at s.t.p = 22.4 dm³

A. 112 cm²
B. 224 cm²
C. 448 cm²
D. 2240 cm²

Question 107:

• JAMB 2005

How many moles of limestone will be required to produce 5.6g of CaO?
[Ca = 40, C = 12, O= 16]

A. 0.20 mol
B. 0.10 mol
C. 1.12 mol
D. 0.56 mol

Question 108:

• JAMB 2005

The density of a certain gas is 1.98gdm^-3 at s.t.p. What is the molecular mas of the gas?

A. 44.0 g
B. 54.0 g
C. 26.0 g
D. 31.0 g

Question 109:

• JAMB 2006

The volume of 2.5 moles of oxygen at s.t.p is
[Molar volume of a gas at s.t.p = 22.4 dm³]

A. 50.0 dm³
B. 84.0 dm³
C. 28.0 dm³
D. 56.0 dm³

Question 110:

• JAMB 2006

What is the molar mass of a substance, if 0.4 mole of the substance has a mass of 25.0g?

A. 62.5 g
B. 40.0 g
C. 6.3 g
D. 2.5 g