Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Paper chromatography
21 practice questions
Practice questions
1–3 of 3 · Hard
Question 1
2 marks · Hard
Answer and see the solution →A blue dye in a chromatography experiment travels 1.5 cm from the pencil line. The solvent front moves 5.0 cm from the pencil line. Calculate the R_f value for the blue dye. Show your working.
Question 2
5 marks · Hard
Answer and see the solution →A student wants to find out whether the green colour in a piece of candy is due to a single dye or a mixture of dyes. Describe how you would carry out a paper chromatography experiment to investigate this. Include details about:
(a)[1 mark]the preparation of the chromatography paper and application of the sample
(b)[1 mark]how to set up and run the chromatography
(c)[1 mark]how to mark the solvent front and why this is important
(d)[1 mark]what you would expect to observe if the green dye is a mixture of dyes
(e)[1 mark]one step you should take to make sure your results are reliable
Question 3
2 marks · Hard
Answer and see the solution →Explain why the R_f value must always be between 0 and 1 in a paper chromatography experiment.