This topic summary covers Knowledge Organiser: Factors Affecting Rate of Reaction within Factors Affecting Rate for GCSE Chemistry. Revise Factors Affecting Rate in Rates of Reaction for GCSE Chemistry with 24 exam-style questions and 18 flashcards. This topic shows up very often in GCSE exams, so students should be able to explain it clearly, not just recognise the term. It is section 13 of 13 in this topic. Use this topic summary to connect the idea to the wider topic before moving on to questions and flashcards.
Knowledge Organiser: Factors Affecting Rate of Reaction
Five Rate Factors (CCTSP)
- Concentration ↑ → more collisions
- Catalyst → lower Ea, more succeed
- Temperature ↑ → faster + more exceed Ea
- Surface area ↑ → more exposed particles
- Pressure ↑ → same as concentration (gases)
Catalyst Key Facts
- Not consumed — can be reused
- Lowers activation energy
- Provides alternative pathway
- Enzymes = biological catalysts
- Does NOT change amount of product
Graph Interpretation
- Steeper gradient = faster rate
- Same final height = same moles reactant
- Higher plateau = more reactant used
- Horizontal = reaction complete
Exam Checklist
- Temperature: 2 effects needed
- Catalyst: "lowers Ea" not "gives energy"
- End with "more successful collisions"
- Graph: compare steepness AND final value
Key Equations
- Rate = amount ÷ time (g/s or cm³/s)
- Rate increases when: concentration ↑, temperature ↑, surface area ↑, catalyst added, pressure ↑ (gases)
- Catalyst: lowers activation energy — same overall ΔH and same yield
Practice questions for Factors Affecting Rate
Which of the following factors does NOT affect the rate of a chemical reaction?
Explain, in terms of particles, why increasing temperature increases the rate of reaction.
Quick recall flashcards
What are the four factors that affect rate of reaction?
Temperature, Concentration, Surface area, Catalyst
What are enzymes?
Biological catalysts - specific and work at certain temperatures