‹ Chemistry simulationsChemistry · A Level 9701 · 37 Analytical techniques (A Level)Six simulations covering Topic 37: a thin-layer plate where the solvent front rises, the spots separate and you measure Rf with a ruler, a gas-liquid chromatogram where peak areas give the percentage composition, a proton NMR spectrum builder with shifts, integration steps, splitting and the D₂O shake, an n+1 rule explorer built from Pascal's triangle, carbon-13 NMR with equivalent carbons coloured the same in 3D and matched to the peaks, and a final puzzle that combines mass spectrometry, infrared and NMR to identify an unknown compound.
The plate is coated with silica, the stationary phase. The solvent, the mobile phase, creeps up it and carries each compound along for as long as it spends dissolved rather than stuck to the silica. Choose a solvent, run the plate, then drag the ruler to the middle of a spot (or click a spot) to measure how far it moved.
A small sample is injected into a heated column. The mobile phase is an inert carrier gas; the stationary phase is a liquid coated on the column walls. Each compound spends a different fraction of its time dissolved in the liquid, so each leaves the column at its own retention time. Inject a sample, then click a peak to read its area.
Pick a compound. Each set of equivalent hydrogens (one environment) gives one group of peaks, at a chemical shift δ measured from TMS at 0. The blue step line is the integration, so a step 3 units high means 3 hydrogens; the number of lines in each group shows the hydrogens on neighbouring carbons. Choose an environment to see which hydrogens in the structure it comes from.
A hydrogen feels the tiny magnetic fields of the hydrogens on the carbon atoms next to it. Each neighbouring hydrogen can point with or against the field, so each one splits every line in two. Choose the group you are looking at and how many hydrogens its neighbours carry, and watch the pattern grow row by row down Pascal's triangle.
In a carbon-13 spectrum there is one peak for each different carbon environment, and no splitting. Carbons that are equivalent by symmetry give a single peak, so the number of peaks can be less than the number of carbon atoms. Pick a molecule: equivalent carbons share a colour in the 3D model and in the spectrum below it. Choose an environment to circle it.
Real analysis uses all the evidence together. Mass spectrometry gives the relative molecular mass, infrared names the functional groups, and NMR shows how the carbon skeleton is put together. Reveal the clues one at a time, then choose which of the four isomers fits all of them.
Six interactive simulations for Cambridge A Level Chemistry 9701 topic 37 Analytical techniques: a TLC plate with a rising solvent front, separating spots and a draggable ruler to measure Rf against known compounds, a gas-liquid chromatogram where clicking a peak gives its area and the percentage composition, a proton NMR spectrum builder for eight compounds with chemical shift, integration steps, n+1 splitting and the D2O exchange test, an n+1 rule explorer that builds each multiplet from Pascal's triangle, carbon-13 NMR where equivalent carbons are coloured the same in a 3D model and matched to the peaks, and an unknown-compound puzzle combining the molecular ion, infrared bands and NMR data.
Six simulations covering Topic 37: a thin-layer plate where the solvent front rises, the spots separate and you measure Rf with a ruler, a gas-liquid chromatogram where peak areas give the percentage composition, a proton NMR spectrum builder with shifts, integration steps, splitting and the D₂O shake, an n+1 rule explorer built from Pascal's triangle, carbon-13 NMR with equivalent carbons coloured the same in 3D and matched to the peaks, and a final puzzle that combines mass spectrometry, infrared and NMR to identify an unknown compound.
Chromatography and NMR is a free, browser-based simulation for Cambridge International AS & A Level Chemistry 9701 (topic 37 Analytical techniques). The course is assessed in Paper 1 (Multiple Choice (AS)), Paper 2 (AS Structured), Paper 3 (Advanced Practical), Paper 4 (A Level Structured), Paper 5 (Planning, Analysis, Evaluation). Syllabus for examination in 2025-2027. There are 6 tabs, each a self-contained experiment with its own controls and live readings, and nothing to install: it runs on a laptop, tablet or classroom projector.
Full syllabus map: A Level Chemistry 9701 topic 37.
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