Purity and separating mixtures

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Question 3
Medium

A forensic scientist uses paper chromatography to analyze the dye components in a blue ink sample from a suspected forged document.

At the end of the chromatography experiment:

  • The solvent front has traveled 88 mm88\text{ mm}88 mm from the pencil start line.
  • One of the separated blue components has traveled 61 mm61\text{ mm}61 mm from the pencil start line.
a.

Calculate the RfR_fRf​ value of this blue component. Give your answer to 2 significant figures.

[2]
b.

Another separated component, dye X, is found to have an RfR_fRf​ value of 0.420.420.42. The analyst knows that a reference sample of brilliant blue dye has an RfR_fRf​ value of 0.780.780.78 under the same experimental conditions.

The analyst claims that dye X is brilliant blue dye. Explain why the analyst is incorrect.

[2]
c.

In this paper chromatography experiment, identify:

  1. the stationary phase
  2. the mobile phase
[2]

Purity and separating mixtures Questions

  1. GCSE
  2. /Chemistry
  3. /Purity and separating mixtures