The Rf R_f\,Rf value of a food colouring dye can be calculated using the equation:
Rf=distance moved by the dyedistance moved by the solvent front R_f = \frac{\text{distance moved by the dye}}{\text{distance moved by the solvent front}} Rf=distance moved by the solvent frontdistance moved by the dyeIn a paper chromatography experiment, a blue dye moved 4.80 cm from the start line, while the solvent front moved a distance of 7.40 cm.
Calculate the Rf R_f\,Rf value for this blue dye.
Give your answer to 2 decimal places.
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.