chemistryTopic 8 · Chemical AnalysisPaper 2Grades 8–9
Can investigators prove where a contaminated medicine came from?
Starting scenario
Sample S gives two chromatography spots with Rf values 0.42 and 0.68. Factory A references are 0.42 and 0.71; Factory B references are 0.39 and 0.68. A flame test is yellow, but the sample may contain several metal ions. Instrumental analysis gives a small extra peak not in either reference.
You will work through 8 staged questions that build up the science you need. Then you will answer one big-picture question from memory, with no checklist to help you — and only afterwards will the full connection map be revealed.