Lesson eLearning

Write the balanced chemical equation for the complete combustion of butane (C4H10) and calculate the mass of CO₂ produced when 5.0 g of butane is burnt in excess oxygen.

medium 3 marks Class 10 · Science · Carbon and its Compounds
Answer
15.2 g

The correct answer is 15.2 g — Mass of CO₂: 0.3448 mol × 44 g mol⁻¹ = 15.2 g.

Step-by-step solution

  1. Determine the molar mass of butane: 4×12 + 10×1 = 58 g mol⁻¹.
  2. Find moles of butane: 5.0 g ÷ 58 g mol⁻¹ = 0.0862 mol.
  3. Balanced combustion: C4H10 + (13/2)O₂ → 4CO₂ + 5H₂O.
  4. Moles of CO₂ formed: 4 × 0.0862 = 0.3448 mol.
  5. Mass of CO₂: 0.3448 mol × 44 g mol⁻¹ = 15.2 g.
Common mistake: Using the wrong coefficient for CO₂ or miscalculating moles of butane

Concept tested: Combustion stoichiometry

Published · How this solution was prepared and checked

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