# Propane and butane are alkanes used as fuels in camping gas canisters. When propane burns completely in excess oxygen, the products are carbon dioxide and water. However, when the oxygen supply is limited, different products can form. Explain what happens when propane undergoes complete combustion and incomplete combustion, and describe why incomplete combustion can be dangerous.

> Edexcel A-Level Chemistry (9CH0) — 6.2 Alkanes · Explain · 5 marks

> Camping gas canisters contain propane (C₃H₈) or butane (C₄H₁₀). These alkanes are used as fuels because they release energy when they burn.

## Mark scheme (5 marks)

1. Complete combustion requires excess/sufficient oxygen
2. Complete combustion produces carbon dioxide and water
3. Incomplete combustion occurs when there is a limited/insufficient supply of oxygen
4. Incomplete combustion produces carbon monoxide (and/or carbon/soot)
5. Carbon monoxide is dangerous because it is a toxic/poisonous gas that can cause death/is colourless and odourless so cannot be detected

## Key terms

- [complete combustion](https://www.gradenine.co.uk/glossary/complete-combustion)
- [incomplete combustion](https://www.gradenine.co.uk/glossary/incomplete-combustion)
- [alkane](https://www.gradenine.co.uk/glossary/alkane)
- [combustion](https://www.gradenine.co.uk/glossary/combustion)

## Related

- [Revision notes for Edexcel A-Level Chemistry (9CH0)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/propane-and-butane-are-alkanes-used-08712520) · Published by Druglandscape Ltd.