This definitions covers Key Definitions 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 7 of 13 in this topic. Make sure you can use the exact wording confidently, because definition marks are often lost through vague language.
📖 Key Definitions
Concentration: The amount of a substance dissolved in a given volume of solution (measured in mol/dm³). Higher concentration means more solute particles per unit volume.
Surface area: The total area of a solid that is exposed and available to react. Smaller particles have a greater surface area-to-volume ratio.
Catalyst: A substance that increases the rate of a reaction by providing an alternative reaction pathway with a lower activation energy. A catalyst is not consumed in the reaction and can be reused.
Enzyme: A biological catalyst — a protein molecule that speeds up reactions in living organisms. Enzymes are specific to one reaction and have an optimum temperature and pH.
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.