This deep dive covers What is Chromatography? 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 2 of 13 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
🔍 What is Chromatography?
Chromatography is a separation technique used to separate mixtures into their individual components and to identify those components.
Two Essential Phases
- Mobile phase: The solvent (e.g. water, ethanol) that moves through or across the stationary phase, carrying dissolved components with it
- Stationary phase: The material that stays fixed in place — in paper chromatography this is the chromatography paper itself
When Do We Use Chromatography?
- To identify what substances are present in a mixture
- To separate components for further analysis
- To test if a substance is pure (one spot) or a mixture (multiple spots)
- To compare unknown samples to known standards (e.g. forensics)
Practice questions for Chromatography
What is the purpose of chromatography?
Explain how a chromatogram can be used to determine whether a substance is pure or a mixture.
Quick recall flashcards
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)
What is chromatography?
A separation technique used to separate mixtures into their individual components based on different affinities for mobile and stationary phases