Topic Four (1.4): Activation Energy and Catalysts

Introduction Icon.png Introduction

This builds on AS Topic 9 (Student Book 1). It distinguishes between homogeneous catalysts and heterogenous catalysts. They work quite differently so make sure you understand the type of catalyst involved. The rate of the reaction can be limited by the quantity of catalyst present, especially heterogenous ones.

Read Icon.png Reading

Edexcel AS/A Level Chemistry Student Book 2 pages 19 to 21

Make Notes Icon.png Tasks

Complete the following:

  • Read pages 19 to 21 and take notes. Take careful note of the subject vocabulary.
  • Complete the ‘checkpoint’ questions.
  • Sketch reaction profiles and write out revision cards for homogeneous catalysts and heterogeneous catalysts.

WATCH - Activation Energy (YouTube) Links to an external site.

WATCH - Catalysts (YouTube) Links to an external site.

WATCH - Iodine Clock Reaction (YouTube) Links to an external site.

Experiments Icon.png Practical Knowledge

Download REVIEW & COMPLETE - CORE PRACTICAL 9b: Iodine Clock

Download CHECK - Core Practical 9B Answers

  • Further questions on these practical exercises can be found on page 22 of the student guide

Top Tip Icon.png Top Tips

Make sure that you understand the following key points:

  • Remember if a reaction is exothermic the reaction could speed up simply due to the release of heat.

Glossary Icon.png Key Terms

Add the following key terms with definitions to your glossary.

  • Adsorption
  • Autocatalysis