Reversible Reactions (AQA GCSE Chemistry): Revision Notes
📚 Revision Notes
6.2.1 Reversible Reactions
Non-Reversible Reactions:
- Some chemical reactions are non-reversible, meaning they can only proceed in one direction, from reactants to products. These reactions are represented using a single arrow (→) pointing from the reactants on the left to the products on the right.
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Example: The reaction between vinegar (ethanoic acid) and sodium hydrogen carbonate:
In this reaction, carbon dioxide is produced as a gas and leaves the reaction, preventing a backwards reaction.
Reversible Reactions:
- In contrast, some chemical reactions can proceed in both the forwards and backwards directions. These are known as reversible reactions.
- In reversible reactions, the products can react with each other to regenerate the reactants.
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Example: The reaction between hydrogen gas and iodine vapour to form hydrogen iodide ($$HI):
- Forward Reaction:
- Backward Reaction:
To simplify notation, instead of writing two separate equations for the forwards and backwards reactions, a single equation is used with a double arrow (⇌) to indicate that the reaction is reversible.
- Reversible Reaction Notation: