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JAMB Chemistry 2008 Question 4

Question 4

Mole Concept and Stoichiometry

16.8g of sodium hydrogen trioxocarbonate (IV) is completely decomposed by heat. Calculate the volume of carbon (IV) oxide given off at s.t.p [Na = 23, C = 12, O = 16, H = 1, Molar volume of a gas at s.t.p. = 22.4 dm3]

  1. A.22.40 dm3
  2. B.11.20 dm3
  3. C.2.24 dm3
  4. D.1.12 dm3.
Show the answer and explanation

Answer: C (2.24 dm3)

Explanation

2NaHCO3 → Na2CO3 + H2O + CO2. 16.8 g ÷ 84 = 0.2 mol NaHCO3, giving 0.1 mol CO2 = 0.1 × 22.4 = 2.24 dm3.