C8 - Paper Chromatography

What is chromatography

Chromatography is a chemical analysis technique used to separate substances in a mixture

What is the name given for the pencil line?

The baseline

Why should we use pencil for the baseline rather than pen?

Pen ink would dissolve in the solvent and move up the paper 

What are some solvents commonly used in chromatography?

Ethanol

Water

What is the name of the resulting paper we end up with?

A chromatogram

The 'mobile phase' refers to the molecules that can move.

Which is the mobile phase in paper chromatography?

The solvent

What happens to a substance which is more soluble

A substance which is more soluble in the mobile phase will spend more time in the mobile phase. This means it will move faster, and travel a further distance up the paper.

The 'stationary phase' refers to the molecules that can't move.

Which is the stationary phase in paper chromatography?

The paper

What happens to a substance that is less soluble

A substance which is less soluble in the mobile phase will spend more time in the stationary phase, so move slower, and not travel very far up the paper

What is the formula to calculate the Rf value

distance travelled by the substance

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distance travelled by the solvent