Chromatography is a way to seperate mixtures to isolate the different components. To seperate the mixtures soluables are added to solvents and then identified depending on they're soluability or being absored into a solid.
To perform a chromatography experiment you need a carrier phase and a stionary phase. In this case during paper chromatography the sample is spotted on the paper and the sample is carried along by the solvent that acts as the moving carrier. Depending on the solubilities of each component of a mixture, the components will be carried different distances. This allows you to get an Rf (ratio of fronts) value.
Rf values can be obtained by diving the distance the solute moved by the solvent front (the distance the solvent travelled). Using Rf values you can differentiate inbetween two substances and identify them accordingly.
Ex: Solute front (d1 the distance the solute traveled) = 3.1cm
Solvent front (d2 the distance the solvent traveled) = 8.1cm
d1/d2=Rf
3.1/8.1=0.382
This Rf value corresponds to the color red so it can be red food coloring.
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