Do I need to memorise the methods for required practicals?

You need to understand the method well enough to answer questions about variables, apparatus, safety, results, and conclusions. The exam will not ask you to write out the full method from memory, but you must be able to describe key steps and explain why they are done.

All 8 GCSE Chemistry Required Practicals: Summary, Methods and Exam Tips

Q: What are the required practicals for AQA GCSE Chemistry?

There are 8 required practicals: (1) Making a soluble salt, (2) Electrolysis, (3) Temperature changes in reactions, (4) Rates of reaction, (5) Chromatography, (6) Testing for ions, (7) Water purification, and (8) Titration. These are examined in Papers 1 and 2.

Q: How are required practicals examined in the GCSE?

Required practicals can appear as structured questions on either Paper 1 or Paper 2. Questions may ask you to identify variables, describe how to improve accuracy, interpret results, suggest improvements, or apply the method to an unfamiliar context. Around 15% of your total marks come from practical-based questions.

Key Takeaways

There are 8 required practicals. They span Topics 1 to 10 and can appear on either Paper 1 or Paper 2.
Around 15% of your total marks come from practical-based questions. You do not perform them in the exam, but you must understand them thoroughly.
Learn the variables for each practical. The independent variable (what you change), dependent variable (what you measure), and control variables (what you keep the same).
Focus on accuracy and improvements. Examiners love asking how to make results more reliable or more accurate.

Required practicals are experiments that AQA says every GCSE Chemistry student should do (or at least understand). You will not be asked to perform them in the exam, but you will be asked questions about the method, variables, results, and conclusions. Here is every one of them, summarised for revision.

RP1: Making a soluble salt

1 Making a soluble salt by reacting an acid with an insoluble reactant Topic 1

Method: Add excess insoluble base (e.g. copper oxide) to warm acid (e.g. sulfuric acid). Stir until no more dissolves. Filter to remove the excess solid. Evaporate the filtrate (slowly, for larger crystals).

Independent variable: the type of acid or base used
Dependent variable: the salt crystals produced
Key skill: knowing when to stop adding the base (when excess remains undissolved)

Exam focus: Why do we add excess base? To ensure all the acid has reacted so the salt solution is pure (no unreacted acid). Why slow evaporation? Larger, more regular crystals form.

RP2: Electrolysis of aqueous solutions

2 Electrolysis of aqueous solutions Topic 2

Method: Set up a circuit with a power supply, two inert electrodes (graphite or platinum), and an electrolyte solution (e.g. copper sulfate, sodium chloride). Observe products at each electrode.

Independent variable: the electrolyte used
Dependent variable: the products at each electrode
Key skill: predicting products using the rules for aqueous electrolysis

Exam focus: At the cathode, the less reactive metal is deposited (or hydrogen if the metal is more reactive than hydrogen). At the anode, halide ions produce the halogen; otherwise, oxygen is produced.

RP3: Temperature changes in reactions

3 Investigating temperature changes Topic 5

Method: Measure the temperature of an acid in a polystyrene cup. Add a measured amount of base (or metal powder). Stir and record the highest (exothermic) or lowest (endothermic) temperature. Calculate the temperature change.

Independent variable: the type or amount of reactant added
Dependent variable: the temperature change
Control variables: volume of acid, starting temperature, concentration

Exam focus: Why use a polystyrene cup? It is an insulator, reducing heat loss to the surroundings. Why stir? To distribute heat evenly. Why use a lid? Further reduces heat loss, improving accuracy.

RP4: Rates of reaction

4 Investigating rate of reaction Topic 6

Method (gas collection): React magnesium with hydrochloric acid and collect the hydrogen gas in a gas syringe. Record the volume at regular time intervals. Plot volume against time.

Method (disappearing cross): Add sodium thiosulfate to hydrochloric acid over a printed cross. Time how long until the cross disappears (due to sulfur precipitate).

Independent variable: concentration (or temperature, or surface area)
Dependent variable: time taken or volume of gas
Control variables: mass of solid, volume of acid, temperature

Exam focus: The steeper the initial gradient of a volume-time graph, the faster the rate. The total volume of gas tells you the amount of product. Increasing concentration, temperature, or surface area all increase rate.

RP5: Chromatography

5 Paper chromatography Topic 8

Method: Draw a pencil line near the bottom of chromatography paper. Place spots of each substance on the line. Stand the paper in a shallow solvent (water line below the pencil line). Wait for the solvent to rise. Remove and dry.

Key skill: calculating R_f values: R_f = distance moved by substance ÷ distance moved by solvent
Key skill: identifying substances by comparing R_f values

Exam focus: Why use pencil (not pen) for the baseline? Pencil is insoluble in the solvent and will not move up the paper. Why must the solvent level be below the spots? So the spots are not washed into the solvent before they can separate.

RP6: Testing for ions

6 Identifying ions Topic 8

Methods:

Flame tests: dip a clean nichrome wire in the sample, hold in a blue Bunsen flame. Lithium = crimson, Sodium = yellow, Potassium = lilac, Calcium = orange-red, Copper = green.
Sodium hydroxide test: add NaOH solution to a sample. A coloured precipitate identifies the metal ion: Cu²⁺ = blue, Fe²⁺ = green, Fe³⁺ = brown, Al³⁺/Ca²⁺/Mg²⁺ = white.
Carbonate test: add acid. If CO₂ is produced (turn limewater milky), the sample contains carbonate ions.
Halide test: add silver nitrate solution (acidified with nitric acid). AgCl = white, AgBr = cream, AgI = yellow.
Sulfate test: add barium chloride (acidified with HCl). White precipitate = sulfate present.

Exam focus: Why clean the wire between flame tests? To avoid contamination from the previous sample. Why acidify before adding silver nitrate or barium chloride? To prevent false positives from carbonate ions.

RP7: Water purification

7 Purifying water by distillation Topic 10

Method: Heat the impure water in a flask. The water evaporates, travels through a condenser (cooled by cold water), and condenses back into liquid water in a collection beaker. Impurities remain in the flask.

Key skill: understanding that distillation separates by boiling point
Key skill: knowing the water is pure if it boils at exactly 100 °C

Exam focus: Distilled water is not the same as potable water. Potable water contains dissolved minerals and is safe to drink. Distilled water is pure H₂O with nothing dissolved, which is not required for drinking.

RP8: Titration

8 Titration Topic 3

Method: Fill a burette with a known concentration of acid. Pipette a fixed volume of alkali into a conical flask. Add indicator. Slowly add acid from the burette until the indicator changes colour (the end point). Record the titre. Repeat until you get concordant results (within 0.10 cm³).

Independent variable: volume of acid added (the titre)
Dependent variable: the colour change of the indicator
Control variables: concentration of acid, volume of alkali, indicator used

Exam focus: Why use a pipette (not a measuring cylinder) for the alkali? Greater accuracy. Why do a rough titre first? To know roughly where the end point is, so you can add slowly near the end. Why discard the rough titre? It is not accurate enough. Average only the concordant titres.

For the full titration calculation method, see our blog post on titration calculations or use our Titration Calculator.

Exam tips for practical questions

Top tips from examiners

Name the variables precisely. Do not say "amount" when you mean "mass" or "volume" or "concentration." Be specific.
"Repeat and calculate a mean" is the standard way to improve reliability. State it clearly.
Safety precautions must be specific. "Wear goggles because the acid is corrosive" is better than "be careful."
Read the graph. If they give you a results table, check for anomalous results and exclude them from your mean calculation.
Resolution matters. A burette (0.05 cm³) is more precise than a measuring cylinder (1 cm³). Mention this when asked about improving accuracy.
Use the correct terminology. "Accurate" means close to the true value. "Precise" means results are close to each other. "Reproducible" means another person gets the same results.

Frequently Asked Questions

What are the required practicals for AQA GCSE Chemistry?

There are 8 required practicals: making a soluble salt, electrolysis, temperature changes, rates of reaction, chromatography, testing for ions, water purification, and titration. They cover Topics 1, 2, 3, 5, 6, 8, and 10.

Do I need to memorise the methods?

You need to understand the method well enough to describe key steps, explain why certain apparatus is used, identify variables, and suggest improvements. The exam will not ask you to write out the full method from memory, but it will test your understanding of it.

How are required practicals examined?

They appear as structured questions on Papers 1 and 2. Around 15% of your total marks come from practical-based questions. Questions may ask you to identify variables, describe how to improve accuracy, interpret results, calculate values, or apply the method to an unfamiliar context.

Explore AQA GCSE Chemistry

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All 8 AQA GCSE Chemistry Required Practicals: The Complete Summary