# Explain how a catalyst increases the rate of a chemical reaction, with reference to activation energy and the Maxwell–Boltzmann distribution.

> IB DP Chemistry Higher 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) for the reaction.
2. This alternative pathway has a lower activation energy.
3. A greater proportion/fraction of molecules have energy greater than or equal to the (lower) activation energy.
4. Therefore the frequency of successful/effective collisions increases, so the rate of reaction increases. The catalyst is not consumed/remains unchanged at the end of the reaction.

## Key terms

- [catalyst](https://www.gradenine.co.uk/glossary/catalyst)
- [activation energy](https://www.gradenine.co.uk/glossary/activation-energy)
- [Maxwell–Boltzmann distribution](https://www.gradenine.co.uk/glossary/maxwell-boltzmann-distribution)

## Related

- [Revision notes for IB DP Chemistry Higher 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)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/explain-how-a-catalyst-increases-the-36e231f8) · Published by Druglandscape Ltd.