A2 Chemistry Chromatography Worksheet

A2 CHEMISTRY CHROMATOGRAPHY WORKSHEET

1 Explain, giving diagrams, the difference between separation by partition and separation by adsorption.

2 Amino acids may be separated by using two-dimensional paper chromatography. This involves putting a spot of the mixture on the corner of a piece of chromatography paper and allowing a solvent to soak up the paper. The paper is then dried, turned through 90°and placed in a second solvent. This method gives better separation than a one solvent method.

(i) Paper chromatography relies on partition between the solvent applied and another phase. What is this second phase?

……………………………………….

3 Write a sentence to explain the difference between paper chromatography and thin layer chromatography.

…………………………………………………………………………………………

4 In gas/liquid chromatography the mobile phase is a ………….. (e.g. …………………..) and the stationary phase is a non-volatile ………………. coated on to small inert particles.

The graph below shows a GLC chromatogram of a mixture of organic chemicals.

(i) Which compound is present in the largest amount? ……………………….

(ii) Which compound has a retention time of 2 mins? ………………………

(iii) What further method must be used to help identify unknown compounds after they have passed through a GLC column? ……………………………..

5 Give 3 differences between gas/liquid chromatography and high performance liquid chromatography.

…………………………………………………………………………………………

…………………………………………………………………………………………..

6 Give one example each of an analytical use of

(i) high performance liquid chromatography

…………………………………………………………………………………………..

(ii) gas/liquid chromatography

………………………………………………………………………………………….