# Explain how the addition of a catalyst increases the rate of a chemical reaction.

> IB DP Chemistry Standard Level (2023 syllabus) — R2.2 How fast? The rate of chemical change · Explain · 4 marks

## Mark scheme (4 marks)

1. A catalyst provides an alternative reaction pathway (mechanism).
2. This alternative pathway has a lower activation energy.
3. A greater proportion/fraction of colliding particles now have energy greater than or equal to the (new, lower) activation energy.
4. The catalyst is not consumed/used up in the overall reaction, so it can continue to catalyse further reactions.

## Key terms

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

## Related

- [Revision notes for IB DP Chemistry Standard Level (2023 syllabus)](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/explain-how-the-addition-of-a-9c4b0213) · Published by Druglandscape Ltd.