Analyse paper and thin layer (TLC) chromatographs to determine the composition and purity of substances, including calculating RF values. Gases

A thin layer chromatography (TLC) experiment was performed to test the purity of a synthetic flavouring compound, vanillin. The solvent front travelled 8.4 cm from the origin, and the vanillin sample produced two distinct spots: one at 6.3 cm and another at 2.1 cm from the origin. Analyse the TLC plate data to: (a) calculate the \(R_f\) value of the major component (the spot at 6.3 cm). (1 mark) (b) explain what the presence of two spots indicates about the purity of the vanillin sample. (1 mark)

A student performed thin layer chromatography (TLC) on a sample of ink to determine its composition. The solvent front travelled 7.2 cm from the baseline, and three distinct spots were observed. Spot X travelled 5.4 cm, spot Y travelled 3.6 cm, and spot Z travelled 1.8 cm from the baseline. Analyse the chromatograph data to determine which spot has the greatest \(R_f\) value and therefore the highest affinity for the mobile phase.

A student performs thin layer chromatography (TLC) to analyse a sample of red food colouring. The solvent front travels 8.0 cm from the origin. One of the separated dyes travels 6.4 cm from the origin. Analyse the data to determine the retention factor (\(R_f\)) for this dye.