GCSE›AQA GCSE Chemistry›Mind mapsCatalystsAQA GCSE Chemistry: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsWhat is it?Changes the rate without being used upDifferent reactions need different catalystsEnzymes are biological catalystsHow it worksGives an alternative pathwayPathway has a lower activation energyMore particles have enough energy when they collideSpotting oneReaction is faster with it presentMass and identity unchanged at the endNot in the balanced equationMnOX2\ce{MnO2}MnOX2 recovered unchanged from HX2OX2\ce{H2O2}HX2OX2 decompositionCatalystsspeeding up reactionsRate basicsMean rate = quantity ÷ time takenSteeper slope = faster rateTangent gradient gives rate at one pointOther factorsConcentration, pressure, surface areaMore frequent collisions raise the rateTemperature raises frequency and energy of collisionsExam tipsCatalyst lowers the activation energy barrierDo not say it lowers reactant or product energyRead rate from steepness, not height