An automated analyser carries out a chemical reaction in a rigid, sealed cartridge. Identical cartridges containing the same reacting mixture are kept at 15 ∘C15\ ^\circ\text{C}15 ∘C and at 35 ∘C35\ ^\circ\text{C}35 ∘C. Which statement about the average time between collisions of the reacting particles at the start of the reaction is correct for the cartridge at 15 ∘C15\ ^\circ\text{C}15 ∘C, compared with the cartridge at 35 ∘C35\ ^\circ\text{C}35 ∘C?
The time between collisions is shorter because the particles are packed closer together when cooler
The time between collisions is unchanged because the quantity of reactant is unchanged
The time between collisions is shorter because fewer of the collisions are successful
The time between collisions is longer because the particles move more slowly
127 exam-style questions on AQA GCSE Chemistry 6.1 Rate of reaction, covering 6.1.1a Calculating rates of reactions, 6.1.1b Gradient of a tangent as rate, 6.1.2 Factors which affect the rates of chemical reactions, 6.1.3 Collision theory and activation energy, and 6.1.4 Catalysts. Each one has a worked solution and a mark scheme showing where the marks go.