Chemical reactions | Post-16 thermodynamics tutorials

Perhaps the most fundamental question in chemistry is ‘why do particular chemical reactions occur?’ More specifically, we want to know why one reaction occurs, while the reverse one does not.

This tutorial encourages students to think about how the random behaviour of particles and quanta of energy gives rise to predictable reactions, taking place in a particular direction. Students explore and develop their understanding of key ideas, including:

• Reversible reactions, or how the direction of some chemical reactions can change
• The importance of chance and the role of statistics in making randomness predictable
• The concept of entropy, and how particles adopt the most probable arrangements by chance alone

The tutorial also features two videos demonstrating the irreversible reaction between magnesium and dilute hydrochloric acid.