A reaction is carried out at 20 ∘C20\,^\circ\mathrm{C}20∘C and then at 40 ∘C40\,^\circ\mathrm{C}40∘C. The rate is greater at 40 ∘C40\,^\circ\mathrm{C}40∘C.
Statement 1: The particles collide more frequently at 40 ∘C40\,^\circ\mathrm{C}40∘C.
Statement 2: A greater proportion of collisions have energy equal to or greater than the activation energy at 40 ∘C40\,^\circ\mathrm{C}40∘C.
Statement 3: The activation energy of the reaction is lower at 40 ∘C40\,^\circ\mathrm{C}40∘C.
Which statements help to explain why the rate is greater at 40 ∘C40\,^\circ\mathrm{C}40∘C?
1 and 2 only
1 and 3 only
2 and 3 only
1, 2 and 3
56 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.