Solid, Liquid, Gas & Aqueous
- State symbols are written after each formula in chemical equations to show which physical state each substance is in
- Brackets are used and they are not usually subscripted although you may come across them written in this way
- Aqueous should remind you of the word 'aqua' and means the substance is dissolved in water
- In other words it is a solution
The four state symbols show the physical state of substances at normal conditions
- Symbol equations should be included when writing chemical equations.
- An example of a reaction with state symbols is the reaction of copper carbonate with hydrochloric acid:
CuCO3 (s) + 2HCl (aq) ⟶ CuCl2 (aq) + CO2 (g) + H2O (l)
Exam Tip
Be careful when writing the state symbol of solutions of liquids. For example, ethanol, or common alcohol, is a liquid at room temperature, so if it is pure alcohol then you would be using (l) as the state symbol; most of the time alcohol is used as a solution in water so (aq) is symbol to use.
