Session 8. Chemical reactions and why they happen

Introduction

So far, you have been largely concerned with atoms, molecules and their electronic and spatial structures, you have not looked in much detail up to this point at chemical reactions themselves and why they happen at all. This will be the topic of this session.

Rather than just discuss this in theoretical terms, to put some of the ideas you will be presented with in context, you will concentrate on one particular reaction which occurs in the modern motor car.

After studying Session 8 you should be able to:

• appreciate the concept of chemical equilibrium and equilibrium constant
• recognise that at equilibrium the amounts of reactants and products are constant but not necessarily the same
• appreciate that at equilibrium the rate of the forward reaction is the same as the rate of the reverse reaction
• understand what is meant by rate of reaction and the influence of catalysts.