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Chemical AnalysisExam Focus

Exam Focus

Part of Chromatography · GCSE GCSE Chemistry revision

This exam focus covers Exam Focus within Chromatography for GCSE Chemistry. Revise Chromatography in Chemical Analysis for GCSE Chemistry with 23 exam-style questions and 15 flashcards. This topic shows up very often in GCSE exams, so students should be able to explain it clearly, not just recognise the term. It is section 11 of 13 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.

Topic position

Section 11 of 13

Practice

23 questions

Recall

15 flashcards

🎯 Exam Focus

Very High Frequency

What Examiners Ask About Chromatography

  • Calculate an Rf value from given distance data (1–2 marks) — show formula and working
  • Describe the method for paper chromatography (3–4 marks)
  • Interpret a chromatogram — how many substances? Which samples match? (2–3 marks)
  • Explain why pencil is used instead of pen (1 mark)
  • Explain why the start line must be above the solvent (1 mark)
  • Explain why substances separate — different solubilities / affinities for phases (2 marks)

AO3 Evaluation Tips

  • Limitations: different substances can have the same Rf; colourless substances need UV detection or chemical developers
  • Improving accuracy: spot size, correct solvent choice, maintaining consistent conditions

Edexcel 1CH0: Examined in Paper 2 (1CH0/2). Edexcel CP10 (paper chromatography) and CP14 (ink chromatography) are both examinable — know how to calculate Rf values and identify substances. In Edexcel-style questions, the command word "Suggest" appears frequently — use your chemistry knowledge to apply to an unfamiliar context.

Keep building this topic

Read this section alongside the surrounding pages in Chromatography. That gives you the full topic sequence instead of a single isolated revision point.

Higher Tier: Other Types of ChromatographyExam Tips for ChromatographyThe Science Behind Solving CrimesWhat is Chromatography?

Practice Questions for Chromatography

What is the purpose of chromatography?

  • A. To separate the components of a mixture
  • B. To measure the mass of a substance
  • C. To change a substance from a solid to a liquid
  • D. To make a substance more concentrated
1 markfoundation

Explain how a chromatogram can be used to determine whether a substance is pure or a mixture.

3 marksstandard

Quick Recall Flashcards

What is chromatography?
A separation technique used to separate mixtures into their individual components based on different affinities for mobile and stationary phases
What does Rf stand for and what does it measure?
Rf = Retention factor. It measures how far a substance travels compared to the solvent (distance moved by substance ÷ distance moved by solvent)

23 questions on Chromatography — practise free

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Higher Tier: Other Types of Chromatography

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Exam Tips for Chromatography