For a reaction between gases, increasing pressure at constant temperature increases rate because
particles are closer together and collide more often
the activation energy is lowered by the pressure
a greater proportion of collisions have enough energy
particles move faster, so they collide more often
127 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.