C8: Separation Techniques, Chromatography and Solubility
Official Cambridge & Imperial ESAT specification requirements for Separation Techniques, Chromatography and Solubility on the Chemistry paper. Understand the syllabus boundaries, spot distractor traps engineered by examiners, and master the 2-step Sub-90 shortcuts that compress solve time well below the 88.8-second cutoff.
Official Syllabus Subtopics
Requirements specified in the UAT-UK framework
- 1Filtration, crystallisation, evaporation, and simple distillation
- 2Fractional distillation of miscible liquids with different boiling points
- 3Paper and thin-layer chromatography (TLC): Rf = distance by spot / distance by solvent front
- 4Solubility curves (grams of solute per 100 g of water)
- 5Recrystallisation mass yields upon temperature reduction
Sub-90 Exam Speed Tips
How top candidates solve this spec under the 88.8s clock
When calculating mass crystallising upon cooling, subtract solubility at lower temperature from that at higher temperature per 100 g water, then scale.
Rf values are always between 0.0 and 1.0; mobile phase affinity increases Rf.
Examiners engineer distractor options using common algebraic expansions and sign slips. Always test structural ratios or invariants before calculating arithmetic values.
Tested Topics in Specification C8
Master the individual question patterns and Sub-90 shortcuts for this specification.
Solubility Curves (g per 100 g Water), Recrystallisation Mass & Paper/TLC Chromatography Rf
Check the exact wording on the mass given: if given M grams of WATER, Precipitate = (M/100)*(S(hot) - S(cold)). If given M grams of SATURATED SOLUTION at T(hot), Precipitate = M * (S(hot) - S(cold)) / (100 + S(hot)).
Ready to Master Specification C8 Under Exam Conditions?
Practice timed questions under the authentic Pearson VUE interface with live split stopwatch pacing, dry-wipe scratchpad, and distractor forensics.