This topic summary covers Topic Summary: Chromatography within Chromatography for GCSE Chemistry. Revise Chromatography in Chemical Analysis for GCSE Chemistry with 20 exam-style questions and 15 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 13 of 13 in this topic. Use this topic summary to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 13 of 13
Practice
20 questions
Recall
15 flashcards
Topic Summary: Chromatography
Key Terms
- Mobile phase: solvent that moves
- Stationary phase: paper (stays fixed)
- Solvent front: furthest point of solvent
- Rf = substance distance ÷ solvent distance
Rf Value Rules
- Always between 0 and 1
- No units
- More soluble → higher Rf
- Same Rf in same solvent = probably same substance
Interpreting Results
- 1 spot = possibly pure substance
- Multiple spots = definitely a mixture
- Matching Rf values → likely same compound
- Spot at baseline = insoluble in solvent used
Practical Technique
- Use PENCIL (not pen) for baseline
- Start line must be above solvent
- Mark solvent front immediately
- Measure from start line to spot centre