AQA GCSE Chemistry · 8462
Specification 4.8.1.3 · Paper 2
- Revise: Chromatography Techniques
A unitless ratio equal to the distance moved by a substance divided by the distance moved by the solvent.
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GCSE Chemistry · key term
The distance travelled by a substance divided by the distance travelled by the solvent front, both measured from the baseline.
Used by AQA, Edexcel and OCR
Specification 4.8.1.3 · Paper 2
A unitless ratio equal to the distance moved by a substance divided by the distance moved by the solvent.
Specification 2.10 · Paper 1
Revise: Interpretation of ChromatogramsA spot’s Rf value expresses how far it travelled compared with the solvent. Mark the solvent front before it becomes difficult to see.
Specification C2.1i, PAG 3 · Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Higher), Paper 4 (Higher)
A unitless ratio comparing the distance travelled by a substance with the distance travelled by the solvent front.
The distance moved by a spot divided by the distance moved by the solvent front, both measured from the start line.
Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Higher), Paper 4 (Higher)
Compare spots or Rf values only when the chromatography conditions are the same. A match suggests an identity but does not prove it.
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