GCSE›Edexcel GCSE Chemistry›Mind mapsReversible Reactions & EquilibriaEdexcel GCSE Chemistry: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsReversibleProducts can re-form the reactantsShown with the ⇌ symbolDirection changes with conditionsDynamic equilibriumNeeds a closed systemForward and backward reactions both continueRates are equalConcentrations stay constant, not equalEquilibriareversible reactions⇌NH3Haber processNX2+3 HX2⇌2 NHX3\ce{N2 + 3H2 <=> 2NH3}NX2+3HX22NHX3Nitrogen from airHydrogen from natural gas450 °C, 200 atm, iron catalystChanging conditionsHigher temperature favours the endothermic directionHigher pressure favours fewer gas moleculesMore reactant shifts equilibrium to productsHaber: 4 gas moles to 2, so pressure favours ammoniaExam tipsEquilibrium does not mean the reaction stoppedLearn the exact Haber conditions