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