There is no coursework in AQA GCSE Chemistry. Instead, the eight required practicals are assessed in the written papers, and questions drawing on practical work make up at least 15% of the marks. The examiner isn’t checking whether you once stood at a bench and did the experiment; they’re checking whether you can describe the method, justify each step, handle the variables and evaluate the results. That makes practicals one of the most learnable parts of the course: everything on this page and its two parts can be revised like any other topic.
How required practicals are assessed
Every required practical can appear in your exams in four ways. Learn each practical with all four in mind:
- Describe: write or order the method steps, name the apparatus, state the measurements taken.
- Explain: justify a step (why excess base? why a polystyrene cup? why pencil, not pen?). This is where most marks live.
- Apply: process results: plot graphs, calculate gradients, Rf values or means, spot anomalies.
- Evaluate: identify errors, suggest improvements, and comment on accuracy, repeatability and validity.
Paper 1 examines RP1–RP4 (topics C1–C5); Paper 2 examines RP5–RP8 (topics C6–C10). RP2 and RP7 are Triple Chemistry only.
Paper 1
Paper 2
Often assessed too
Practical Language That Earns Marks
Every practical question is marked in the same vocabulary. These definitions (and the safety “matched pair”) apply to all eight required practicals.
Practical vocabulary
- Repeatable: the same person, using the same method and equipment, gets similar results on repeating.
- Reproducible: different people, often with different equipment, get similar results. (The tougher test: it’s how science checks a claim.)
- Accurate: a measurement close to the true value.
- Precise: repeated measurements close together (a small spread). Not the same as accurate: tight readings can still all be off the true value.
- Valid: the experiment measures what it’s meant to, because the other variables were controlled (a fair test).
- Resolution: the smallest change an instrument can detect (a balance reading to 0.01 g has a higher resolution than one reading to 1 g).
- Anomalous result: a result that doesn’t fit the pattern. Look for a cause, and if it came from a poor measurement, leave it out of the mean.
- Interval: the gap between values of the independent variable (e.g. testing concentrations 10 g/dm3 apart). Choose a sensible range and intervals: too narrow a range and the pattern may not show.
- Categoric vs continuous: a categoric variable is a label (the type of metal); a continuous one is a measured number (temperature, volume). This choice decides the graph: categoric → bar chart, continuous → line graph.
- Calibration / zero error: checking an instrument against a known value. A balance reading non-zero with nothing on it is a zero error: tare it (or subtract the offset) before weighing.
Tables and graphs are marked too
Practical questions regularly award marks for how you record and present the data. Easy marks if you know the checklist:
- Tables. The independent variable in the first column, headings with units in the heading (so the cells are just numbers), and a column for repeats and the mean.
- Choosing the graph. Categoric independent variable (type of metal) → bar chart; continuous (concentration, temperature, time) → line graph.
- Drawing it. Sensible scales that use more than half the grid, both axes labelled with quantity and unit (independent variable on the x-axis, dependent on the y), points plotted accurately (±half a small square), and a line of best fit, a smooth line or curve through the trend, not dot-to-dot, ignoring anomalous points, drawn once, cleanly (feathered, doubled or sketchy lines lose the mark).
- Trial runs. A quick rough go (like RP2’s rough titration) finds sensible values and the right range before you collect the real data.
- Significant figures. Give calculated values (means, rates, Rf) to a sensible number of significant figures, matching the data: a mean of times measured to the nearest second shouldn’t be quoted to five figures.
- Straight-line graphs. A straight line means a linear relationship: this is the y = mx + c idea from maths, where the gradient (m) is how fast one variable changes with the other and the intercept (c) is the starting value. In chemistry you’re asked for the gradient and intercept in context, not the equation, and if the line passes through the origin, the two variables are directly proportional.
Five habits that work in every practical question
- Never write “amount”. Say exactly what you are changing, measuring or keeping the same: the mass, volume, concentration or number of moles. “The same volume of acid”, not “the same amount of acid”.
- Safety is a matched pair. Name the hazard, give the precaution that targets it, and say what harm it prevents.
- Observation, then inference. Write down what you would see (“the cross is no longer visible”, “a white precipitate forms”), and keep it separate from what it means.
- Right + wrong = wrong. A correct point contradicted elsewhere in the same answer is cancelled. Mark schemes do not let a wrong extra ride along with a right one. Don’t scatter alternatives to “cover all eventualities”; commit to the correct one.
- Six-markers: task → sequence → judgement. Work out exactly what the question needs you to produce, put the steps in an order that would actually work, and, if the command implies a decision, state the judgement. Length adds nothing; structure is what moves an answer up a level.