GCSE›Edexcel GCSE Chemistry›Mind mapsRates of ReactionEdexcel GCSE Chemistry: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsMeasuring rateGas volume over time: gas syringeMass lost over time on a balanceMarble chips + HCl gives CO₂Thiosulfate + HCl: cloudy sulfurTime for a mark to disappearCollision theoryParticles must collideWith at least the activation energyRate rises with collision frequency or energyChanging conditionsTemperature: more frequent and more energeticConcentration: more particles in same volumePressure: particles closer togetherSurface area: more particles exposedReaction rateshow fast reactions goscm³gReading graphsSteeper gradient = faster rateGraph flattens when a reactant is used upCatalystsSpeed up a reaction, not used upLower activation energy pathwayEnzymes are biological catalystsYeast enzymes make alcoholic drinksExam tipsOnly temperature raises collision energy tooCatalyst: name the lower activation energyThiosulfate: shorter time = faster rate