Chromatography sim
The solvent (the mobile phase) soaks up the paper (the stationary phase) and carries each dye a fixed share of the way: a dye more soluble in the solvent goes further.
Chromatography · covers the GCSE, IGCSE, O-Level topic
What the sim shows
The solvent (the mobile phase) soaks up the paper (the stationary phase) and carries each dye a fixed share of the way: a dye more soluble in the solvent goes further. The pencil line is in pencil because graphite does not dissolve; the solvent must start below it, or the spots dissolve into the jar; the lid keeps the air full of solvent vapour so the front rises evenly. Take the paper out before the front reaches the top and mark the front at once. Rf = distance moved by the spot ÷ distance moved by the solvent, both measured from the pencil line, so it lies between 0 and 1 and has no units. Spots at the same height are the same substance. The dyes' Rf values are this figure's examples. The clock runs 30 times faster than real time.
- Dyes keep their own colour
- Right: the paper close up, ruler from the pencil line
Use it in your lessons
- Try it here: anyone can unlock 2 figures free, and a free account unlocks up to 5. Runs on a laptop, a Chromebook or a phone; nothing to install.
- Present it and share student links with the teacher plan, from US$5 a month, billed yearly.
- Put it on your own website or LMS for US$9, paid once, or every sim from US$29 a month.
Free guide: 12 practicals as sims, and how to run one in a lesson →
Need a version for your exact set-up? Have one made: US$49 a figure in an order of 5.
More chemistry sims
- Iron and sulfur: mixture or compound? simPull iron out of an iron and sulfur mixture with a magnet, then heat a fresh mixture until it glows and forms black iron(II) sulfide, which the magnet no longer attracts, and find the fixed proportion from your own masses.
- Making a salt by titration simTitrate with methyl orange, repeat with the same volumes and no indicator, then crystallise sodium chloride, sodium sulfate or the fertiliser ammonium sulfate and work out the yield.
- Making a standard solution and diluting it simWeigh a solid, dissolve it, transfer it with rinsings to a volumetric flask, make up to the mark and invert; then dilute with a pipette. Concentrations in mol/dm³ and g/dm³, and what each slip in technique does to them.
- Which metal oxides can carbon reduce? simHeat the oxides of magnesium, zinc, iron, lead and copper with carbon, in hydrogen, and in competition with other metals. Real data decide each result, and a results table builds the reactivity series and shows why each metal is extracted the way it is.
- Moles of gas from magnesium and acid simWeigh magnesium ribbon, drop it into hydrochloric acid and collect the hydrogen in a gas syringe. Plot the volume against moles of magnesium to measure 24 dm³ per mole, and watch the line level off when the acid runs out.
- Neutralising acid with lime simAdd weighed spatulas of calcium hydroxide or calcium oxide to dilute hydrochloric acid, stir, read the pH meter and plot pH against mass added; then lime a pot of acid soil.