See the whole course
The practical map
8 practical activities across the chemistry topics, and one repeatable way to think: what changes, what you measure, what stays the same, and what the evidence can honestly support.
- 1Making a soluble saltTrilogy 1
- 2TitrationTrilogy 2
- 3ElectrolysisTrilogy 3
- 4Temperature changesTrilogy 4
- 5Rates of reactionTrilogy 5
- 6ChromatographyTrilogy 6
- 7Identifying ionsSeparate
- 8Water purificationSeparate
Showing 8 practicals
Making a soluble salt
The word 'pure' is worth marks: every step exists to remove something.
- Question
- Prepare pure, dry copper sulfate crystals from dilute sulfuric acid and insoluble copper oxide.
- Change or compare
- No investigative variable; the prescribed acid and insoluble base determine the salt made.
- Measure or observe
- Formation and quality of the pure, dry copper sulfate crystal sample.
Open the exam playbook
Method in beats
- Wear eye protection and warm a measured volume of dilute sulfuric acid gently in a water bath.
- Add small portions of copper oxide while stirring until fresh solid no longer reacts and some remains in excess.
- Filter the mixture to remove the excess copper oxide, collecting the blue copper sulfate solution as filtrate.
- Heat the filtrate gently in an evaporating basin until some water has evaporated and the solution is concentrated.
- Stop heating before the solution dries out and leave it to cool so crystals form.
- Separate the crystals from the remaining solution and dry them between clean filter papers.
Control
- volume and concentration of sulfuric acid
- warming and evaporation conditions
- addition of copper oxide until a visible excess remains
- clean apparatus and drying method
Graph or record
No graph. The evidence is a flow of steps: warm acid, add excess base, filter, evaporate to crystallisation point, leave to dry.
Calculation
Percentage yield = (actual mass ÷ theoretical mass) × 100. Theoretical mass comes from the balanced equation and moles of the limiting reactant.
Safety cue
- Wear eye protection; dilute sulfuric acid and copper sulfate solution can irritate or harm eyes and skin.
- Avoid inhaling copper oxide powder and clean spills using the school's chemical-safety procedure.
- Use a water bath or gentle controlled heating, handle hot glassware carefully and do not heat the solution to dryness.
Classic trap
Filtering too early. The excess insoluble base must be filtered off, then the solution evaporated gently; boiling to dryness gives a damp, impure solid.
Revise it inside Chemical Changes – AQA GCSE Chemistry Revision Guide →
Titration
Precision is the whole point: swirl, add dropwise near the end point, read at eye level.
- Question
- Determine accurately the volumes of a strong acid and strong alkali that react completely.
- Change or compare
- Volume of solution delivered from the burette.
- Measure or observe
- Indicator end point and the corresponding titre.
Open the exam playbook
Method in beats
- Rinse the pipette with the solution it will measure, then transfer a fixed volume into a conical flask.
- Add a few drops of one suitable indicator, such as phenolphthalein or methyl orange, and place the flask on a white tile.
- Rinse and fill the burette with the other solution, remove the funnel and record the initial reading at eye level.
- Run solution into the flask while swirling; use a rough titration to locate the end point.
- Repeat, adding solution dropwise near the sharp colour change, then record the final burette reading.
- Calculate titre = final reading − initial reading, recording burette readings to the precision of the scale.
- Repeat until concordant titres are obtained and calculate their mean, excluding the rough result and justified anomalies.
Control
- fixed pipetted volume
- concentrations and identities of the acid and alkali
- indicator identity and number of drops
- apparatus rinsing and eye-level reading technique
Graph or record
No graph. Present titres in a table, mark the rough titre, and show the mean of concordant values to two decimal places.
Calculation
Concentration (mol/dm³) = moles ÷ volume in dm³; use the mean titre (concordant results within 0.10 cm³) and the mole ratio from the equation.
Safety cue
- Wear eye protection and rinse acid or alkali splashes from skin immediately with plenty of water.
- Clamp the burette securely and fill it below eye level, using a funnel that is removed before readings.
- Handle glass pipettes and burettes carefully; use a pipette filler, never mouth pipetting.
Classic trap
Averaging the rough titre with the accurate ones, or reading the burette from the top of the meniscus.
Revise it inside Chemical Changes – AQA GCSE Chemistry Revision Guide →
Electrolysis
Predict the products first, then let the tests confirm or embarrass you.
- Question
- Investigate the products formed at inert electrodes when different aqueous ionic solutions are electrolysed.
- Change or compare
- Identity of the dissolved ionic compound.
- Measure or observe
- Substance formed and identified at each electrode.
Open the exam playbook
Method in beats
- Add a measured volume and concentration of one aqueous electrolyte to a labelled container.
- Insert clean inert electrodes at a fixed depth and separation, then connect them to a low-voltage direct-current supply.
- Switch on for a fixed time and record bubbles, colour changes or solid deposits separately at each electrode.
- Collect any gas in small inverted test tubes without swapping the cathode and anode samples.
- Test hydrogen with a lighted splint, oxygen with a glowing splint and chlorine with damp litmus paper, using only small samples.
- Switch off, clean the electrodes and repeat with the other solutions under the same conditions.
Control
- solution concentration and volume
- electrode material, area, depth and separation
- supply voltage and electrolysis time
- gas-collection and identification method
Graph or record
No graph. Record the gas tests: squeaky pop for hydrogen, relit splint for oxygen, bleached damp litmus for chlorine.
Calculation
Write half equations at each electrode, for example 2Cl⁻ → Cl₂ + 2e⁻ at the anode and 2H⁺ + 2e⁻ → H₂ at the cathode.
Safety cue
- Wear eye protection and use the low-voltage direct-current supply with dry hands.
- Use small quantities in good ventilation; chlorine is toxic, so do not inhale gases and stop after enough is collected for the test.
- Follow school hazard guidance for each electrolyte, including harmful copper compounds, and wash hands after the practical.
Classic trap
Forgetting that hydrogen forms at the cathode when the metal is more reactive than hydrogen, and that oxygen forms at the anode unless a halide ion is present.
Revise it inside Chemical Changes – AQA GCSE Chemistry Revision Guide →
Temperature changes
The thermometer is your evidence that bonds forming release more energy than bonds breaking take in.
- Question
- Measure how hydrochloric acid concentration affects the maximum temperature rise when it reacts with sodium hydroxide solution.
- Change or compare
- concentration of dilute hydrochloric acid
- Measure or observe
- maximum temperature rise of the neutralisation mixture
Open the exam playbook
Method in beats
- Using its own clean, dry, labelled measuring cylinder, measure 25.0 cm³ of teacher-approved dilute hydrochloric acid into an insulated polystyrene cup supported in a beaker.
- Using a separate clean, dry, labelled measuring cylinder, measure 25.0 cm³ of fixed-concentration sodium hydroxide into a labelled beaker and fit a lid to the cup.
- Measure each reactant with a clean probe. Rinse it with distilled water and dry it between solutions; once both readings are steady at the same starting temperature, record them.
- Pour the sodium hydroxide into the acid, replace the lid, stir with the temperature probe and record at fixed intervals until the maximum passes.
- Calculate maximum temperature rise, rinse and dry the apparatus, then repeat with a fresh teacher-approved acid concentration.
- Repeat every concentration, calculate mean temperature rises and plot mean rise against hydrochloric acid concentration.
Control
- 25.0 cm³ volume of each reactant
- concentration of sodium hydroxide solution
- same measured starting temperature for both reactants
- same insulated cup, lid, probe, stirring and reading intervals
Graph or record
Line graph: volume or concentration of acid on the x-axis, temperature change on the y-axis; a peak marks the point of complete neutralisation.
Calculation
Temperature change = highest temperature − starting temperature. Compare changes across concentrations or volumes of acid.
Safety cue
- Wear eye protection and use only teacher-approved dilute hydrochloric acid and sodium hydroxide concentrations and quantities.
- Avoid skin contact; rinse splashes or spills promptly with plenty of water and follow the teacher's local instructions.
- Keep the polystyrene cup supported in a beaker and carry the separate reactant beaker carefully before mixing.
Classic trap
Reading the temperature too early or too late, and not using a lid and polystyrene cup to reduce heat loss.
Revise it inside Energy Changes – AQA GCSE Chemistry Revision Guide →
Rates of reaction
Rate is a gradient. Every rates question is really a graph question.
- Question
- Test concentration using both a gas-volume method and a separate colour-or-turbidity method.
- Change or compare
- concentration of one reactant
- Measure or observe
- gas volume over time or time to a fixed turbidity endpoint
Open the exam playbook
Method in beats
- Develop the hypothesis that increasing reactant concentration increases rate because particles collide more often, producing more successful collisions each second.
- Before every trial, use fresh reactants and clean, rinsed and dried apparatus; for turbidity, confirm the cross is visible before mixing.
- Gas method: measure 25.0 cm³ of teacher-approved dilute hydrochloric acid at a stated concentration, such as 0.50, 1.00 or 1.50 mol/dm³, into a conical flask.
- Add 0.20 g of same-size marble chips (calcium carbonate), immediately fit the bung to a freely moving 100 cm³ gas syringe, and start timing at first contact using the same start-and-seal routine each time.
- Record the carbon dioxide volume at regular intervals until the reading plateaus; repeat for each acid concentration.
- Turbidity: make a sodium thiosulfate concentration series by replacing some solution with water, keeping total volume and viewing depth fixed. Add the same dilute hydrochloric acid volume each time and start timing.
- Stop timing when the cross is no longer visible through the same depth of mixture, viewed from the same position.
- Repeat each concentration and calculate means. For gas curves at all tiers, draw a tangent at time zero and compare its steepness.
- Higher Tier: calculate the initial tangent gradient in cm³/s.
- For turbidity, calculate relative rate = 1/mean time.
- Plot the Higher Tier gas method's numerical initial rate or the turbidity method's relative rate against concentration, then test the hypothesis.
Control
- temperature
- reactant volumes
- solid mass and surface area for gas method
- same apparatus and endpoint rule
Graph or record
Line graph of volume of gas against time; the gradient of the tangent at a point gives the rate at that moment, and a steeper start means a faster reaction.
Calculation
Mean rate = amount of product formed ÷ time, for example cm³ of gas per second, or 1 ÷ time for the disappearing cross.
Safety cue
- Wear eye protection and use only teacher-approved dilute acid and reactant quantities.
- Sodium thiosulfate with acid releases sulfur dioxide; use a well-ventilated laboratory, small quantities and the teacher's local risk controls.
- Keep the gas syringe pointed away from people, check that it moves freely and do not use sealed apparatus without an expansion path.
- Do not lean directly over the reaction vessel; clear spills using the teacher's instructions.
Classic trap
Changing the temperature or volume by accident when only concentration should change, and starting the timer late.
Revise it inside Rate and Extent of Chemical Change – AQA GCSE Chemistry Revision Guide →
Chromatography
Pencil line, solvent below the line, lid on. Three habits, most of the marks.
- Question
- Separate coloured mixtures by paper chromatography and calculate Rf values from the finished chromatogram.
- Change or compare
- sample or solvent being compared
- Measure or observe
- spot pattern, distance moved and calculated Rf
Open the exam playbook
Method in beats
- Draw a pencil origin line above the solvent. Use a separate clean capillary for each sample; apply a small, concentrated spot and let each application dry before re-spotting.
- Stand the paper in a covered container with the solvent below the origin; keep it upright and avoid touching the sides.
- Allow the solvent to rise, remove the paper before it reaches the top and mark the solvent front immediately in pencil.
- Dry the paper, mark spot centres, measure distances from the origin and calculate Rf values.
- Repeat with standards or another solvent if the identification needs stronger evidence.
Control
- paper type and dimensions
- origin and solvent depth
- spot volume and drying
- development time and temperature
Graph or record
No graph. Measure from the pencil baseline to the centre of each spot and to the solvent front, then compare Rf values with known substances.
Calculation
Rf = distance moved by the spot ÷ distance moved by the solvent front. Rf has no units and is always less than 1.
Safety cue
- Wear eye protection and follow the school hazard guidance for the selected solvent and samples.
- Keep volatile or flammable solvents covered and away from flames, hot equipment and ignition sources.
- Avoid skin contact and use the solvent only in the teacher-approved quantity and ventilation.
Classic trap
Drawing the baseline in ink (it dissolves and runs) or letting the solvent level start above the baseline.
Revise it inside Chemical Analysis – AQA GCSE Chemistry Revision Guide →
Identifying ions
Separate Chemistry only: one unknown compound, a logical order of tests, and a conclusion you can defend.
- Question
- Use flame, hydroxide and anion tests to identify the ions in teacher-provided unknown single ionic compounds.
- Change or compare
- identity of the teacher-provided unknown
- Measure or observe
- flame colour, gas result or precipitate colour and behaviour
Open the exam playbook
Method in beats
- Plan a test sequence from the possible ions and label a fresh portion of unknown for each branch.
- Carry out a flame test on a clean wire loop where appropriate and record the colour.
- Add sodium hydroxide solution dropwise, then in excess where needed; record precipitate colour and solubility.
- Test fresh portions for carbonate, halide or sulfate using the correct acid and reagent sequence.
- Compare observations with known controls and report evidence before the final identity.
Control
- sample amount and concentration
- reagent identity, concentration and volume
- clean apparatus and separate sample portions
- flame conditions where used
Graph or record
No graph. A results table with the test, the observation and the ion identified is the expected format.
Calculation
No calculation. Match each observation to its ion: flame colours for metal ions, precipitate colours with sodium hydroxide, and the tests for carbonate, halide and sulfate ions.
Safety cue
- Wear splash-proof eye protection and follow the school's risk assessment throughout.
- Use only small, teacher-approved quantities; acids, alkalis and several test reagents can irritate or damage skin and eyes.
- Keep hair and loose clothing secured around a lit Bunsen burner; extinguish it when flame testing is complete.
- Treat barium and silver reagents and unknowns as hazardous laboratory chemicals; avoid contact and dispose of them in labelled school waste, not the sink.
- Do not deliberately inhale gases; use the specified test at the tube mouth or by transferring gas as directed.
Classic trap
Testing for a halide before adding dilute nitric acid, so carbonate ions give a false precipitate with silver nitrate.
Revise it inside Chemical Analysis – AQA GCSE Chemistry Revision Guide →
Water purification
Separate Chemistry only: test, distil, test again. Purity is something you demonstrate.
- Question
- Measure water-sample properties, purify water by simple distillation and collect the distillate using teacher-approved samples.
- Change or compare
- water sample or treatment stage
- Measure or observe
- pH, dissolved-solid residue or distillate properties
Open the exam playbook
Method in beats
- Split each water sample into separate labelled aliquots before adding indicator, evaporating or distilling; never reuse a treated aliquot for another comparison.
- Observe and record the sample, then measure pH with indicator or a calibrated probe. Rinse the probe with distilled water and blot it dry between samples.
- If the sample contains suspended material, filter it before measuring the aliquot for dissolved solids. Use the same filter-paper grade, funnel and filtration procedure for every comparable sample.
- Dry an empty evaporating basin, allow it to cool and record its mass.
- Measure a known volume of water into the basin and heat gently to evaporate the water without spitting.
- Cool and reweigh the basin and residue; if directed, repeat the heat-cool-weigh cycle to constant mass. Subtract the empty-basin mass to find the dissolved-solid residue mass.
- Set up simple distillation with anti-bumping granules before heating.
- Heat gently, cool vapour in the condenser and collect the distillate; stop heating before the distillation flask boils dry.
- Compare starting water and distillate using the planned measurements.
Control
- starting sample volume
- filter-paper grade, funnel and filtration procedure when filtration is needed
- apparatus and heating conditions
- measurement method
Graph or record
Bar chart of dissolved-solids mass for each water sample; pH is recorded in a table rather than plotted.
Calculation
Mass of dissolved solids = mass of the evaporating basin after evaporation − mass of the empty basin; compare samples using the same starting volume.
Safety cue
- Wear eye protection and use only teacher-approved water samples; never taste laboratory water.
- Use a heatproof mat, clamp glassware securely and check it for damage before heating.
- Do not seal the apparatus; point openings away from people and allow hot glassware to cool before handling.
- Use an electric heater or teacher-approved heat source and follow the school's risk assessment.
Classic trap
Calling distilled water 'pure' without a test: pure water boils at exactly 100 °C and leaves no residue on evaporation.
Revise it inside Using Resources – AQA GCSE Chemistry Revision Guide →
Decode the command
What the question is really asking
A six-mark method and an evaluation question may use the same experiment, but they ask your brain to do different jobs.
Make the comparison fair
Name what changes, what you measure, the controls that matter, sensible repeats and a safe, ordered method.
Write actions, not intentions.Turn readings into evidence
Do the calculation the question needs, choose the right table or graph, then describe the pattern precisely: gradient, intercept, proportionality.
Pattern first; explanation second.Find the weak link
Identify a specific limitation, explain how it changes the evidence, then propose a practical improvement that addresses it.
Problem → consequence → fix.Quick confidence checks
Revision checklist
Mark a practical confident only when you can name its variables, calculation, graph and biggest trap without opening the playbook.
Clear up the awkward bits
Frequently asked questions
How many AQA GCSE Chemistry required practicals are there?
Eight in the Separate Chemistry qualification (8462). Six are shared with Combined Science: Trilogy; identifying ions and water purification are Separate Chemistry only.
Does 'Separate Chemistry only' mean Higher Tier only?
No. The course route (Combined Science or Separate Chemistry) and the tier (Foundation or Higher) are different things. Separate-only practicals can be examined at either tier.
Do I have to memorise the exact method?
No. Questions test whether you can plan a valid, safe method and interpret the evidence. Know the purpose of each step, the variables, the calculation and the common mistake, and you can reconstruct any version of the method.
Which chemistry practicals involve calculations?
Titration (concentration from the mean titre), making a salt (percentage yield), rates (rate from a gradient or 1 ÷ time), chromatography (Rf values), temperature changes (temperature rise) and water analysis (mass of dissolved solids).
How are required practicals examined?
At least 15% of the marks across the two papers assess practical knowledge: planning, variables, apparatus, safety, graphs, calculations and evaluation. There is no coursework or practical exam.