Chromatography Required Practical

This lesson follows the AQA Combined Science Trilogy specification (spec link: 5.8.1.3 Chromatography) in the Chemical Analysis chapter of the Kerboodle book (numbered C8 or C10 depending on your edition — worth double-checking against your copy), but is also suitable for Separate Science GCSE Chemistry students.

What’s Included: (25 slides)

Do now retrieval & thinking task – recap of mixtures, separation methods, and solubility, plus a challenge question on why substances travel at different speeds through paper
Worked examples – step-by-step Rf value calculations, including rearranging the equation to find distance travelled by the solute
Numeracy tasks – calculating Rf values from given distances, then using the Rf equation to find missing distances
Pure and impure substances theory – comparing single vs multiple spots on a chromatogram to identify purity, with a mini whiteboard check using reference inks
Diagram-based numeracy checks – calculating Rf values from labelled chromatograms, with an extension task on matching Rf values between substances
Required practical method – separating coloured substances by paper chromatography, from baseline to measuring Rf values
Six mark practice – planning a full investigation to identify an unknown ink, with a model answer
Common experimental errors – baseline drawn in pen, solvent level above the baseline, and not marking the solvent front immediately
Tiered practice questions – low, medium, and high demand exam-style questions, including drawing conclusions from chromatogram results
Homework task – applying knowledge of pure substances and chromatography, with mark allocations

Answer slides included for all structured questions and review tasks.

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