Chromatography: separating a mixture of inks
I can identify the composition of inks using paper chromatography.
Chromatography: separating a mixture of inks
I can identify the composition of inks using paper chromatography.
These resources will be removed by end of Summer Term 2025.
Lesson details
Key learning points
- Chromatograms can identify unknown substances through comparison or Rf values.
- Appropriate equipment should be used during comparisons, and calculations should consider significant figures.
- A fair comparison of chromatograms depends on stationary and mobile phase choices, sample concentration and temperature.
- Chromatograms can be used to identify pure and impure substances.
Keywords
Solvent front - The solvent front is the furthest distance the solvent travels along the stationary phase during chromatography.
Sample line - The sample line is where the sample undergoing chromatography is placed on the stationary phase.
Rf value - The Rf value is a ratio describing the distance a component of a sample travelled, in relation to the distance the solvent travelled under the same conditions.
Chromatogram - A chromatogram is the resultant pattern on the stationary phase after chromatography has been carried out.
Common misconception
Pupils can struggle to interpret information that contains several samples on one chromatogram.
Stress a systematic approach to interpreting chromatograms - use rulers. Live model this - using a visualiser helps enormously.
Content guidance
- Risk assessment required - equipment
Supervision
Adult supervision required
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Lesson video
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