MEDIUM
Upper Secondary: IGCSE
IMPORTANT
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The diagram below shows a chromatogram for a mixture of amino acids. 

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The solvent was a mixture of water, butanol and ethanoic acid. Using the table of Rfvalues given, identify the two amino acids.

Important Questions on Separating Substances

MEDIUM
Upper Secondary: IGCSE
IMPORTANT
Complete Chemistry for Cambridge IGCSE® Second Edition>Chapter 2 - Separating Substances>Checkup on Chapter 2>Q 8

The diagram below shows a chromatogram for a mixture of amino acids.

Question ImageQuestion Image

The solvent was a mixture of water, butanol and ethanoic acid. Which of them is less soluble in the solvent?

MEDIUM
Upper Secondary: IGCSE
IMPORTANT
Complete Chemistry for Cambridge IGCSE® Second Edition>Chapter 2 - Separating Substances>Checkup on Chapter 2>Q 8

The diagram below shows a chromatogram for a mixture of amino acids. 

Question Image

Amino acid Rf value
Cysteine 0.08
Lysine 0.14
Glycine 0.26
Serine 0.27
Alanine 0.38
Proline 0.43
Valine 0.60
Leucine 0.73

The solvent was a mixture of water, butanol and ethanoic acid. How will the Rfvalues change if the solvent travels only 6cm?

HARD
Upper Secondary: IGCSE
IMPORTANT
Complete Chemistry for Cambridge IGCSE® Second Edition>Chapter 2 - Separating Substances>Checkup on Chapter 2>Q 9
You have three colourless solutions. Each contains an amino acid you must identify. Explain how to do this using chromatography. Use the term Rfand locating agent in your answer, and show that you understand what they mean.