Some reactions are over before you can blink — an explosion, or a precipitate appearing the instant two solutions meet. Others, like the rusting of iron, take years. C6 asks two questions about every reaction: how fast it goes (the rate), and how far it goes (the extent — because some reactions can run backwards too). Industry asks exactly the same two questions of every process it runs, which is why this topic is full of real chemical engineering.
🧭 How this topic splits by tier
Within C6 itself (4.6) there is no Triple-only content — Combined Science and Triple Chemistry students learn the same material here, and the only split is by tier:
- Everyone — calculating mean rates, drawing and interpreting rate graphs, drawing tangents, the factors affecting rate, required practical 5, collision theory, catalysts, reversible reactions and dynamic equilibrium.
- Higher Tier H — calculating the gradient of a tangent as the rate at a specific time, using mol/s as a unit of rate, and the whole of section 7: Le Chatelier’s principle and the effects of changing concentration, temperature and pressure on equilibrium.
Calculating Rates of Reaction
Factors Affecting Rate
Changing Equilibrium Conditions
H
Capstone
Bringing It Together