Chromatography for SQA National 5 Chemistry

Chromatography

This page covers the following topics:

1. Formulations
2. Chromatography
3. Rf values

Formulations are complex mixtures of chemicals which have a specific use.

Formulations

Chromatography can be used to identify the substances present in a mixture of solutes.

Chromatography

Chromatograms can be identified by calculating the Rf values for the separated components of mixtures.

Rf values

1

Calculate the Rf value for the blue ink in the chromatogram shown.

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0.425

Calculate the Rf value for the blue ink in the chromatogram shown.

2

In a paper chromatography experiment, the yellow coloured ink is found to not move up the paper. What is the retention factor? Why does the ink not move?

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0 - the yellow ink is not soluble in the solvent used.

In a paper chromatography experiment, the yellow coloured ink is found to not move up the paper. What is the retention factor? Why does the ink not move?

3

In a paper chromatogram, the solvent travels 7.2 cm up the paper. The Rf value for red ink is 0.5. How far did the red ink travel up the paper?

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3.6 cm

In a paper chromatogram, the solvent travels 7.2 cm up the paper. The Rf value for red ink is 0.5. How far did the red ink travel up the paper?

4

Calculate the Rf value for the purple ink in the chromatogram shown.

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0.75

Calculate the Rf value for the purple ink in the chromatogram shown.

5

Which is an example of a formulation: a block of pure iron, cough syrup, oxygen gas.

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Cough syrup.

Which is an example of a formulation: a block of pure iron, cough syrup, oxygen gas.

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