Key learning points

1. A chemical equation is used to represent the chemical reaction that occurs during the formation of a compound.
2. Ionic equations can be used to show only the chemical species that are changing within a reaction.
3. State symbols (s), (l), (g) and (aq), are used in ionic equations to show which substances change.
4. The ionic equation for water formation (neutralisation) is H⁺(aq) + OH⁻(aq) → H2O(l).

Common misconception

Keywords

• State symbol - used in chemical equations to indicate the physical state of a substance

• Ionic equation - a balanced equation showing all the ions involved in a reaction

• Spectator ion - ions not involved in a chemical reaction

• Oxidation - a type of reaction in which a substance gains oxygen or loses electrons

• Reduction - a type of reaction in which a substance loses oxygen or gains electrons