This exam focus covers Exam Focus: Rates of Reaction within Rates & Collision Theory for GCSE Chemistry. Revise Rates & Collision Theory in Rates of Reaction for GCSE Chemistry with 25 exam-style questions and 16 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 11 of 14 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.
🎯 Exam Focus: Rates of Reaction
This topic appears in virtually every GCSE Chemistry paper. Examiners love asking students to explain rate changes using collision theory — not just describe them.
very-high Explain questions (3-4 marks): You must state: (1) the factor changed, (2) how it affects collision frequency or energy, (3) how this changes the number of successful collisions, (4) the result on rate.
high Graph interpretation (2-3 marks): Steeper curve = faster rate. Same final height = same amount of product. Curve stopping = reaction complete.
high Calculation questions (2 marks): Rate = amount ÷ time. Use the gradient of the tangent to a curve for instantaneous rate.
Key command words: "Explain" = collision theory mechanism required. "Describe" = state what happens on the graph. "Calculate" = show working with units.
Edexcel 1CH0: Examined in Paper 2 (1CH0/2). Edexcel tests collision theory with reference to concentration, temperature, particle size and catalysts — expect to explain rate changes using collision frequency and activation energy. In Edexcel-style questions, the command word "Suggest" appears frequently — use your chemistry knowledge to apply to an unfamiliar context.
Practice questions for Rates & Collision Theory
According to collision theory, which of the following must happen for a chemical reaction to take place?
Explain, using collision theory, why increasing the concentration of a reactant solution increases the rate of reaction.