G3 Chemistry: the practical paper explained

Paper 3 of G3 Chemistry (K324) is the hands-on practical — 40 marks, 20% of the grade, about 1 hour 50 minutes. It assesses four skill areas: planning an experiment, manipulating apparatus and recording observations, presenting data, and analysing results to a conclusion.

The four assessed skills

The practical is marked across four skill areas. Planning (P) — designing a procedure — carries about 15% of the paper. The other 85% comes from Manipulation, Measurement & Observation (MMO) (handling apparatus and recording accurately), Presentation of Data & Observations (PDO) (tables and graphs done correctly), and Analysis, Conclusions & Evaluation (ACE) (drawing valid conclusions and judging reliability).

Titration

A titration question rewards precision. Burette readings are taken to the nearest 0.05 cm³, and you aim for two concordant titres within 0.20 cm³ before averaging. Marks are lost on untidy tables, missing units, and using a rough titre in the average. Familiarity with a burette with a tap is expected, and you may be asked to use a data-logger.

Qualitative analysis (QA)

In QA you identify ions by their reactions. You test cations (such as Al³⁺, Ca²⁺, Cu²⁺, Fe²⁺, Fe³⁺, Zn²⁺, NH₄⁺) with sodium hydroxide and ammonia, and anions (carbonate, chloride, iodide, nitrate, sulfate) with the matching reagents — observing precipitates, colours and gases. The QA notes are printed in the paper, so the skill is careful observation and correct deduction, not memorising every result cold.

Note two things K324 does not examine in the practical: drying of gases, and tests involving sulfur dioxide gas.

Presenting data and observations

Easy marks live in presentation. Tables need clear headings with units; readings should be to a consistent precision; graphs need sensible scales, correctly plotted points and a line of best fit where appropriate. Significant figures and units are marked throughout — a right number with the wrong unit still loses the mark.

How to prepare

Practical skill is built by doing, then reviewing. Drill titration technique and table layout until they are automatic, rehearse the QA tests so observations come quickly, and practise writing conclusions that actually use the data. LearnUp runs practical drills calibrated to the K324 skill areas alongside the theory.