State Symbols (AQA GCSE Combined Science: Trilogy): Revision Note Exam code: 8464

State Symbols (AQA GCSE Combined Science: Trilogy): Revision Note

Exam code: 8464

What are state symbols?

  • State symbols:

    • show which physical state each substance is in

    • are written after each formula in brackets in chemical equations

    • are sometimes shown as subscript, e.g NaOH(aq)

Solid

Liquid

Gas

Aqueous

(s)

(l)

(g)

(aq)

  • Aqueous should remind you of the word 'aqua' and means the substance is dissolved in water

    • In other words it is a solution

  • State symbols 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)

Examiner Tips and Tricks

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.


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