A student cools sodium thiosulfate solution and dilute hydrochloric acid before mixing them. The cross under the flask takes longer to disappear than when the solutions are mixed at room temperature.
The student says, "Cooling decreases the rate because it increases the activation energy of the reaction."
Explain why the student's statement is incorrect.
122 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.