Paper chromatography

1 mark · Easy

How should you measure the distance a dye has travelled on a chromatogram to calculate its R_f value?

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From the pencil line to the centre of the dye spot.

Also accept: To the centre of the spot; From the pencil line (baseline) to the centre of the dye spot

Common mistakes: To the edge of the spot; From the bottom of the paper

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Marking points

B1 · 1 mark · Specifies measuring from the pencil line to the centre of the dye spot.

Worked solution

You should measure from the pencil line (starting line) up to the centre of the dye spot.