Paper chromatography
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What this model shows
Two prepared samples on paper, at room temperature: the green food dye U beside known dyes A and B in water, then a colourless sample C in a suitable solvent, revealed with a locating agent.
The spots travel a fixed fraction of the solvent’s distance (U’s blue spot and A 0.35, U’s yellow spot and B 0.70; C’s spots 0.30 and 0.65). Real Rf values depend on the paper, the solvent and the temperature. Time is compressed and spot sizes are illustrative.
Real solvents and locating agents need a teacher-approved procedure. Never taste samples; keep flammable solvents away from flames.
With reduced motion, each step finishes at once, and the solvent climbs 2 cm at a time.
Select a piece of equipment, on the bench or here, to read about it in the card.
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