Cambridge IGCSE Chemistry · Syllabus 0620 · Chemical Reactions
Reversible Reaction
What is Reversible Reaction?
A reaction in which the products can react together to re-form the original reactants, so that the change can proceed in both directions. It is written with the equilibrium symbol, a pair of opposed half-arrows, instead of a single arrow.
This definition is part of the Chemical Reactions chapter in Cambridge IGCSE Chemistry.
Common mistakes with Reversible Reaction
- 11. “The flat part of the graph shows equilibrium.” Core 6.2.4 Supplement 6.3.3 Why temptingNothing is changing, which is what equilibrium looks like. RepairIn an open flask the curve flattens because a reactant has run out and the reaction has stopped. Equilibrium needs a closed system and two reactions still running at equal rates. TransferWhat two things does a vessel need before it can reach equilibrium? A reversible reaction, and a seal so that no product escapes. Marble and acid fails the first test — carbon dioxide, calcium chloride and water do not react back — so sealing that flask alone would achieve nothing.