# Explain why alkanes are described as saturated hydrocarbons and why they do not readily undergo addition reactions.

> Cambridge International IGCSE Chemistry (0620) — 11.4 Alkanes · Explain · 4 marks

## Mark scheme (4 marks)

1. Alkanes contain only carbon–hydrogen and carbon–carbon bonds / contain no double (or multiple) bonds
2. Saturated means all carbon atoms have the maximum number of hydrogen atoms / no more hydrogen atoms can be added
3. Addition reactions require a double bond / C=C bond for atoms to add across
4. Because alkanes have only single (sigma) bonds, they undergo substitution reactions instead of addition reactions

## Key terms

- [saturated](https://www.gradenine.co.uk/glossary/saturated)
- [hydrocarbon](https://www.gradenine.co.uk/glossary/hydrocarbon)
- [addition reaction](https://www.gradenine.co.uk/glossary/addition-reaction)

## Related

- [Revision notes for Cambridge International IGCSE Chemistry (0620)](https://www.gradenine.co.uk/learn)
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Source: [GradeNine](https://www.gradenine.co.uk/q/explain-why-alkanes-are-described-as-f6a24a93) · Published by Druglandscape Ltd.