Increasing pressure speeds the Haber reaction because
particles are closer, so they collide more often
the activation energy of the reaction is lowered
a greater proportion of collisions have enough energy
the particles move faster and have more energy
43 exam-style questions on Edexcel GCSE Chemistry 6.3 Dynamic equilibria, covering 6.3.1 The Haber process as a reversible reaction, 6.3.2 Conditions and rate in industrial equilibria, and 6.3.3 Fertilisers and the preparation of ammonium sulfate. Each one has a worked solution and a mark scheme showing where the marks go.