# Explain why heavy fuel oil fractions from crude oil are less useful as fuels than petrol fractions.

> AQA GCSE Chemistry (8462) — 4.7.1 Carbon compounds as fuels and feedstock · Explain · 4 marks

## Mark scheme (4 marks)

1. Heavy fuel oil has longer hydrocarbon molecules / larger molecules than petrol
2. Heavy fuel oil is more viscous / does not flow as easily as petrol
3. Heavy fuel oil has a higher boiling point / is harder to vaporise than petrol
4. Heavy fuel oil is less flammable / ignites less easily than petrol

## Key terms

- [fractions](https://www.gradenine.co.uk/glossary/fractions)

## Related

- [Revision notes for AQA GCSE Chemistry (8462)](https://www.gradenine.co.uk/learn)
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