BRAINCAKEThe rate and extent of chemical change
Revision notes for The rate and extent of chemical change in AQA Combined Science: Trilogy (8464). Every lesson in BrainCake comes with R.E.C.I.P.E. recall steps, a quick check and spaced reviews.
- Calculating rates of reactionsThe rate of reaction tells you how fast reactants are used up or how fast products are formed.
- Factors which affect the rates of chemical reactionsFive factors change the rate of a chemical reaction.
- Collision theory and activation energyCollision theory explains how factors change the rate of reaction.
- CatalystsA catalyst changes the rate of a chemical reaction but is not used up during it.
- Reversible reactionsMost reactions go one way: reactants turn into products and that is the end of it.
- Energy changes and reversible reactionsEnergy is transferred in every reversible reaction, and the changes in the two directions are linked.
- EquilibriumThink of a reversible reaction in a container that is sealed, so nothing can escape.
- The effect of changing conditions on equilibrium (HT only)The relative amounts of all the reactants and products at equilibrium depend on the conditions of the reaction.
- The effect of changing concentration (HT only)Take the reversible reaction A + B ⇌ C + D at equilibrium.
- The effect of temperature changes on equilibrium (HT only)Changing the temperature of a system at equilibrium also changes the relative amounts of reactants and products.
- The effect of pressure changes on equilibrium (HT only)Pressure only affects a reversible reaction at equilibrium if gases are involved.