# Cracking is an important industrial process. Describe what cracking is and explain why the petrochemical industry carries out cracking on fractions obtained from crude oil.

> Edexcel GCSE Chemistry (1CH0) — 8.1 Fuels · Describe and Explain · 4 marks

> Crude oil is separated into fractions by fractional distillation. Some fractions are in much greater supply than demand requires, whilst other fractions are in very high demand but short supply.

## Mark scheme (4 marks)

1. Cracking breaks down larger/longer-chain hydrocarbons into smaller/shorter-chain molecules
2. Cracking can be done by catalytic cracking or steam cracking
3. Some fractions (longer-chain/heavier) are in excess / low demand and need to be converted into more useful/shorter-chain products
4. Cracking produces shorter-chain, more useful molecules such as fuels (e.g. petrol/diesel) and/or alkenes which are in high demand

## Key terms

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

## Related

- [Revision notes for Edexcel GCSE Chemistry (1CH0)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe and 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/cracking-is-an-important-industrial-process-948de090) · Published by Druglandscape Ltd.