JAMB Chemistry 1981 Question 23

Question 23

Mole Concept and Stoichiometry

Na₂CO₃ + 2HCl → 2NaCl + H₂O + CO₂. Using the above equation, what volume of carbondioxide, measured at s.t.p is liberated when 53 g of sodium carbonate is dissolved in hydrochloric acid? (1 mole of gas occupies 22.4 dm³ at s.t.p) (Na = 23, C = 12, O = 16)

A.44.8 dm³
B.11.2 dm³
C.3.0 dm³
D.100.1 dm³
E.22.4 dm³

Show the answer and explanation

Answer: B (11.2 dm³)

Explanation

Molar mass of Na₂CO₃ = 106 g, so 53 g is 0.5 mol. It gives 0.5 mol CO₂ = 0.5 × 22.4 = 11.2 dm³.