Practical Techniques
Thin Layer Chromatography
Technique
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Draw a pencil line approximately 1cm from the bottom of the paper. Mark a cross and produce a concentrated spot of the compounds to be used by repeated application followed by drying.
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Mark a reference spot (known compound).
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Mark a spot of unknown substance.
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Place in chromatography tank; ensure that the spots are above the solvent.
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Cover with lid.
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Allow time for the solvent to run up the chromatography plate, so it reaches just below the end of the paper.
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Use locating agent to find spots, e.g. iodine, UV light etc.
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Compare the unknown compound with the reference compound.
Reflux
This is a method used to heat a reaction for an extended period of time without losing gaseous reagents/products.
Useful books for revision
Revise A2 Chemistry for Salters (OCR A Level Chemistry B)
Salters (OCR) Revise A2 Chemistry
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