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Edexcel IAL Chemistry Rf Values and TLC

Practise Edexcel IAL Chemistry Rf values in paper chromatography and TLC, using baselines, solvent fronts, spot distances and phase attractions.

Syllabus
First assessment 2019
Course
Chemistry YCH11
Level
A2

Exam points

  • Calculate Rf from chromatogram distances, avoiding reciprocal or whole-plate measurement errors.
  • Complete TLC diagrams with a baseline, labelled solvent front and spot position matching the stated Rf value.
  • Explain low or high Rf values through polarity, solubility and mobile versus stationary phase attractions.

15.22—Rf values from one-way chromatograms in paper and thin-layer chromatography (TLC) and understand reasons for differences question 1

[Maximum number: 1]

This question is about chromatography.

A spot caused by an amino acid has moved 42 mm from the baseline of a paper chromatogram.
The RfR_{\mathrm{f}} value for the amino acid under these conditions is 0.62 .
What is the distance moved by the solvent?

A

680 mm

B

68 mm

C

42 mm

D

26 mm

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