A catalyst is added to one of two otherwise identical reactions. Which statement explains the faster rate?
The catalyst lowers the activation energy, so more collisions succeed
The catalyst makes the particles collide with each other more often
The catalyst gives particles extra energy, so they move faster
The catalyst raises the energy of the reactants, so they react more easily
122 exam-style questions on Edexcel GCSE Chemistry 8.1 Rates of reaction, covering 8.1.1 Measuring and interpreting rates of reaction, 8.1.2 Collision theory and the factors affecting rate, and 8.1.3 Catalysts and enzymes. Each one has a worked solution and a mark scheme showing where the marks go.