Describe the complete combustion of ethanol and state one use of ethanol that depends on this property.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
Ethanol reacts with oxygen:
C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O
The reaction releases energy as heat.
Ethanol is used as a fuel, for example in spirit burners or as a bio‑fuel in vehicles.
C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O
The reaction releases energy as heat.
Ethanol is used as a fuel, for example in spirit burners or as a bio‑fuel in vehicles.
Examiner tips
- Use the balanced equation, include O₂ and CO₂/H₂O, mention heat release, give a specific fuel use
- Keep answer concise, use correct chemical symbols and units
Common mistakes
- Writing an incomplete equation, e.g. missing O₂ or CO₂
- Failing to mention the heat released
- Giving a non‑fuel use such as a solvent
Mark scheme (4 marks)
- Ethanol reacts with oxygen during complete combustion
- Products of complete combustion are carbon dioxide and water
- Energy / heat is released during the reaction
- A use of ethanol that depends on combustion, e.g. fuel / used in spirit burners / used as a biofuel in vehicles
Key terms in this question
Related
- All Cambridge International IGCSE Chemistry (0620) revision notes →
- How to answer a "Describe" question →
- Decode the mark scheme abbreviations →
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