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Reversible Reaction

Key Stage 4

Meaning

Reversible Reactions are reactions in which the products of that reaction, may themselves react to form the original reactants.

About Reversible Reactions

Reversible reactions use the symbol ⇌ to show that the reaction can happen both ways.
A reaction mixture which can undergo a reversible reaction will reach a state of dynamic equilibrium where there is a constant amount of the reactants and products as the reaction keeps happening in both directions.
Since some reactions may be exothermic and others may be endothermic, then one direction of reaction will provide energy to the environment while the other direction will absorb, that same amount of, energy.

Examples

Hydrogen + Nitrogen ⇌ Ammonia

\( 3H_2(g) + N_2(g) ⇌ 2NH_3(g) \)

Calcium Oxide + Carbon Dioxide ⇌ Calcium Carbonate

\( CaO(aq) + CO_2(g) ⇌ CaCO_3(s) \)

Ammonium Chloride ⇌ Ammonia + Hydrochloric Acid

\( NH_4Cl(s) ⇌ NH_3(g) + HCl(g) \)

Extra Information

References

AQA

Reversible reactions, pages 129-30, GCSE Combined Science Trilogy 2, Hodder, AQA
Reversible reactions, pages 138-145, 159 GCSE Chemistry; Third Edition, Oxford University Press, AQA
Reversible reactions, pages 158-9, GCSE Chemistry, Hodder, AQA
Reversible reactions, pages 181-185, GCSE Combined Science Trilogy; Chemistry, CGP, AQA
Reversible reactions, pages 213-217, GCSE Chemistry, CGP, AQA
Reversible reactions, pages 72, 73, 104, GCSE Chemistry; The Revision Guide, CGP, AQA
Reversible reactions; Dynamic equilibrium, pages 130-5, GCSE Combined Science Trilogy 2, Hodder, AQA
Reversible reactions; dynamic equilibrium, pages 159-64, GCSE Chemistry, Hodder, AQA
Reversible reactions; Energy changes, pages 130, GCSE Combined Science Trilogy 2, Hodder, AQA
Reversible reactions, pages 129-30, GCSE Combined Science Trilogy 2, Hodder, AQA
Reversible reactions, pages 138-145, 159 GCSE Chemistry; Third Edition, Oxford University Press, AQA
Reversible reactions, pages 158-9, GCSE Chemistry, Hodder, AQA
Reversible reactions, pages 181-185, GCSE Combined Science Trilogy; Chemistry, CGP, AQA
Reversible reactions, pages 213-217, GCSE Chemistry, CGP, AQA
Reversible reactions, pages 72, 73, 104, GCSE Chemistry; The Revision Guide, CGP, AQA
Reversible reactions; Dynamic equilibrium, pages 130-5, GCSE Combined Science Trilogy 2, Hodder, AQA
Reversible reactions; dynamic equilibrium, pages 159-64, GCSE Chemistry, Hodder, AQA
Reversible reactions; Energy changes, pages 130, GCSE Combined Science Trilogy 2, Hodder, AQA

Edexcel

Reversible reactions, page 121, GCSE Combined Science; The Revision Guide, CGP, Edexcel
Reversible reactions, page 59, GCSE Chemistry; The Revision Guide, CGP, Edexcel
Reversible reactions, pages 169-174, GCSE Chemistry, CGP, Edexcel
Reversible reactions, pages 94, 120, G GCSE Chemistry, Pearson, Edexcel

OCR

Reversible reactions, page 134, Gateway GCSE Combined Science; The Revision Guide, CGP, OCR
Reversible reactions, pages 160, 186-191, 196, 200-203, Gateway GCSE Chemistry, Oxford, OCR
Reversible reactions, pages 73, 74, 80, 82, Gateway GCSE Chemistry; The Revision Guide, CGP, OCR