A laboratory checks four materials before using them as reference samples.
| Record | Particles present in the material |
|---|---|
| R | silver atoms only |
| S | carbon dioxide molecules only |
| T | water molecules only |
| U | water molecules and sodium chloride particles |
Only chemically pure materials may be used as reference samples. Which record shows a material that must be rejected?
Record S
Record R
Record U
Record T
113 exam-style questions on AQA GCSE Chemistry 8.1 Purity, formulations and chromatography, covering 8.1.1 Pure substances, 8.1.2 Formulations, and 8.1.3 Chromatography. Each one has a worked solution and a mark scheme showing where the marks go.