A supplier tested four batches of solid laboratory reagents. The accepted melting points and the measured results are shown in the table.
| Batch | Reagent | Accepted melting point in ∘C^\circ\text{C}∘C | Measured melting temperature in ∘C^\circ\text{C}∘C |
|---|---|---|---|
| K | naphthalene | 80 | 75 to 78 |
| L | naphthalene | 80 | 80 |
| M | stearic acid | 69 | 69 |
| N | stearic acid | 69 | 64 to 67 |
Which two batches gave melting results consistent with pure substances?
Give the letters.
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.