Propane (C₃H₈) is a hydrocarbon used as a fuel in camping stoves. Explain why propane is described as a hydrocarbon and describe what happens when propane burns completely in a plentiful supply of air.

Eduqas GCSE Chemistry — 2.6 Carbon chemistry / organic chemistry · Explain and Describe · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (4 marks)

Propane is a hydrocarbon because it is composed only of carbon and hydrogen atoms.

When propane burns in a plentiful supply of air it reacts with oxygen:
C₃H₈ + 5O₂ → 3CO₂ + 4H₂O.

Thus complete combustion produces carbon dioxide and water.

Examiner tips

  • Use the term ‘hydrocarbon’ and state it contains only C and H.
  • Show the balanced combustion equation or at least the products CO₂ and H₂O.
  • Mention that air supplies the required O₂ for the reaction.
  • Keep the answer concise – 4 marks only.

Common mistakes

  • Writing propane as a hydrocarbon but not specifying it contains only C and H.
  • Omitting the balanced equation or the products CO₂ and H₂O.
  • Confusing incomplete combustion (CO) with complete combustion.

Mark scheme (4 marks)

  1. A hydrocarbon contains hydrogen and carbon only
  2. Propane reacts with oxygen (from the air)
  3. Carbon dioxide is produced
  4. Water is produced

Key terms in this question

hydrocarbon

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