Required Practical 7 Flashcards by siobhan mills

Q

Describe how pigments can be isolated using paper chromatography

A

crush leaves with solvent to extract pigments
draw pencil line on filter paper 1cm above bottom
add drop of pigment to line
place paper in solvent below origin line
remove before solvent reaches top and mark solvent front with pencil

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Q

Rf value

A

Distance moved by spot / distance moved by solvent

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Q

Why are Rf values used not distances

A

solvent moves different distances
Rf value is constant for same pigment / can be compared

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