On a chromatogram, the solvent front travels 9.0 cm. Dye X has Rf=0.72R_f=0.72Rf=0.72. How far does X travel?
8.28 cm8.28\,\mathrm{cm}8.28cm
6.48 cm6.48\,\mathrm{cm}6.48cm
9.72 cm9.72\,\mathrm{cm}9.72cm
12.5 cm12.5\,\mathrm{cm}12.5cm
107 exam-style questions on Edexcel GCSE Chemistry 3.2 Methods of separating and purifying substances, covering 3.2.1 Pure substances and mixtures, 3.2.2 Techniques for separating mixtures, 3.2.3 Paper chromatography and Rf values, and 3.2.4 Making water potable. Each one has a worked solution and a mark scheme showing where the marks go.