As a chemical reaction progresses, the reactant particles are used up and the rate of reaction decreases.
Explain, in terms of particles, why the rate of reaction decreases.
87 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.