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8.1 Purity, formulations and chromatography

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Question 18

A water-quality laboratory uses paper chromatography to test a coloured contaminant. Using the centre of a spot gives an Rf R_f\,Rf​ value of 0.58.

A technician uses the same chromatogram and the same solvent-front distance but obtains an Rf R_f\,Rf​ value of 0.54.

Which distance did the technician most likely use as the distance moved by the substance?

[1]
A

From the origin line to the lower edge of the spot

B

From the bottom edge of the paper to the centre of the spot

C

From the origin line to the upper edge of the spot

D

From the bottom edge of the paper to the upper edge of the spot

Markscheme

8.1 Purity, formulations and chromatography Questions

  1. GCSE
  2. /Chemistry
  3. /8.1 Purity, formulations and chromatography

113 exam-style questions on AQA GCSE Chemistry 8.1 Purity, formulations and chromatography, covering 8.1.1 Pure substances, 8.1.2 Formulations, and 8.1.3 Chromatography. Each one has a worked solution and a mark scheme showing where the marks go.

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