01Purity and Formulations
In chemistry, 'pure' means something very specific — and it's not what most people think. This video explains the scientific definition of a pure substance, shows you how to test for purity using melting and boiling points, and reveals why a sharp, fixed transition temperature is the key signal to look for. You'll also see how mixtures produce the smeared, imprecise transitions that give them away — directly relevant to the chemical analysis section of your exam.
02Analysing Paper Chromatography
This video unpacks paper chromatography from start to finish — the underlying principle, the required practical technique, and how to calculate and use Rf values to identify substances. By the end you'll understand not just how to carry out the experiment, but why each step matters and how to interpret a chromatogram as evidence.
03Tests for Common Gases
04Tests for Ions
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