How to revise GCSE Combined Science Chemistry

A practical plan for Chemistry based on how the topics, the practicals and the papers really fit together. Every link goes to a free page.

Yumio is not affiliated with, endorsed by or connected to AQA, Pearson Edexcel or any exam board. Check your own board's specification for the final word.

1. Know your papers

AQA: Chemistry Paper 1 is 70 marks in 1 hour 15 minutes, covering Atomic structure and the periodic table, Bonding, structure, and the properties of matter, Quantitative chemistry, Chemical changes, Energy changes. Chemistry Paper 2 is 70 marks in 1 hour 15 minutes, covering The rate and extent of chemical change, Organic chemistry, Chemical analysis, Chemistry of the atmosphere, Using resources.

Edexcel: Chemistry Paper 1 is 60 marks in 1 hour 10 minutes, covering Key concepts in chemistry, States of matter and mixtures, Chemical changes, Extracting metals and equilibria. Chemistry Paper 2 is 60 marks in 1 hour 10 minutes, covering Key concepts in chemistry, Groups in the periodic table, Rates of reaction and energy changes, Fuels and Earth science.

Full details: AQA papers and Edexcel papers.

2. Start with the easier topics

The topics graded 1 to 3 on Yumio are Atoms, compounds, mixtures and equations, The periodic table and electronic structure. Secure these first so that a third of every paper feels familiar.

3. Leave room for the hardest ideas

Yumio grades these 7 or above: Alkenes, alcohols and carboxylic acids, Equilibrium: predicting shifts and the Haber compromise, Extracting metals by electrolysis, Gas volumes, pH, strong acids and weak acids, Polymers, The mole and reacting masses, Exam calculations: moles, solutions, titration and yield, Titrations and their calculations. They need the easier topics underneath them, so they come last in your plan.

4. Practise the core practicals as questions

Exam questions often describe an experiment and ask about the method, the variables or the result. Yumio has a chemistry practicals lesson covering: Planning a fair test; Hazards and risk; Making a pure, dry sample of a salt; Neutralisation, pH and temperature change; Electrolysis of copper sulfate solution; Measuring the rate of a reaction. Read it at Chemistry practicals. Two habits that earn marks: say how you keep the test fair; and link a colour or gas test to the ion or gas it shows.

5. Learn the key terms

Use the Chemistry key terms page: exam answers are marked on the exact idea, so a precise word is worth a mark.

6. Avoid the slips that cost marks

• Atoms, compounds, mixtures and equations: Changing a small number inside a formula to balance an equation. Only change the big number in front. Changing H₂O to H₂O₂ makes a different substance.
• Maths skills for chemistry: Using cm³ in a concentration without converting to dm³. Divide cm³ by 1000 to get dm³ first.
• Corrosion, alloys and materials: Saying iron rusts in water only. Iron needs both oxygen and water to rust.
• Life cycle assessments, recycling and getting metals sustainably: Saying an LCA only looks at the use of a product. It covers raw materials, manufacture and packaging, use, and disposal, with transport at each stage.
• Concentration and limiting reactants: Using the volume in cm³ in a concentration calculation. Divide by 1000 to get dm³ first.
• Reversible reactions and equilibrium: Saying the concentrations are equal at equilibrium. They are constant, not necessarily equal.

7. Test yourself without notes

After each topic, answer its questions cold, then check. Use the practice questions for a second set on the same topic. Long answers are marked by level, so link your points rather than listing them.

Questions students ask

How to revise Combined Science overall · All Chemistry topics