Explain why increasing the temperature of a reaction mixture increases the rate of reaction.

Edexcel GCSE Chemistry (1CH0) — 7.1 Rates of reaction · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (4 marks)

Increasing the temperature gives the reacting particles more kinetic energy. Consequently they collide more often and with greater speed. A higher proportion of the collisions now have energy equal to or greater than the activation energy. Therefore more collisions are successful per unit time, so the rate of reaction increases.

Examiner tips

Use the word "explain" to show cause and effect, not just state facts.
Mention kinetic energy, collision frequency, activation energy and successful collisions in that order.
Include the phrase "rate of reaction increases" to link to the question.
Use UK spelling (e.g. "collisions").

Common mistakes

Failing to mention the activation energy or successful collisions.
Using vague terms like "more energy" without linking to kinetic energy or collision frequency.
Writing in the passive voice or omitting the cause–effect structure.

Mark scheme (4 marks)

Particles have more kinetic energy (at higher temperature)
Particles collide more often / more frequently
A greater proportion of particles have energy equal to or greater than the activation energy
There are more successful collisions per unit time, so the rate of reaction increases

Key terms in this question

rate of reaction