How does a catalyst increase the rate of a reaction?
It gives the reactant particles more energy, so more collisions succeed.
It increases the energy change of the reaction, so more energy is released.
It provides an alternative reaction pathway with a lower activation energy.
It increases the number of reactant particles in the same volume.
122 exam-style questions on OCR GCSE Chemistry 5.2 Controlling reactions, covering 5.2.1 Measuring and interpreting rate of reaction, 5.2.2 Factors affecting rate and collision theory, and 5.2.3 Catalysts, activation energy and enzymes. Each one has a worked solution and a mark scheme showing where the marks go.