Cambridge IGCSE·Co-ordinated Sciences 0654·Chemistry
Rate Of Reaction
Key knowledge — Rate Of Reaction
Formulas & equations
Rate of reaction = amount of product formed (or reactant used) ÷ time
Key facts & rules
- Collision theory: reaction occurs when particles collide with sufficient energy (≥ activation energy) and correct orientation.
- Temperature ↑: more frequent collisions AND more particles have energy ≥ Ea → rate increases.
- Concentration ↑ (or pressure ↑ for gases): more frequent collisions → rate increases.
- Surface area ↑ (smaller particles): more exposed particles → more frequent collisions → rate increases.
- Catalyst: provides alternative reaction pathway with lower activation energy → more particles have enough energy → rate increases (not consumed).
- Measuring rate: volume of gas produced per second, or decrease in mass per second, or colour change.
- A graph of volume vs time: steeper gradient = faster rate; gradient decreases as reactants are used up.
IGCSE Chemistry — Rate of reaction
1114 Cambridge IGCSE 0654 chemistry past paper questions on rate of reaction, organised by subtopic. Pick a subtopic to start practising.
About rate of reaction on IGCSE 0654
How concentration, temperature, surface area and catalysts change the rate of a reaction, and how rate is measured.