Four liquids, W, X, Y and Z, were heated until they boiled. Pure propanone boils at 56 ∘C56\ ^\circ\text{C}56 ∘C and pure ethanol boils at 78 ∘C78\ ^\circ\text{C}78 ∘C.
Table: The temperature or temperature range over which each of the four liquids, W, X, Y and Z, boiled
| Liquid | Temperature at which the liquid boiled in ∘C^\circ\text{C}∘C |
|---|---|
| W | 78 |
| X | 56 to 78 |
| Y | 56 |
| Z | 61 to 74 |
Use Table.
Give the letters of the two liquids that are pure substances.
Use Table.
Name the two substances that liquid X is a mixture of.
Give a reason for your answer.
A student says that liquid Z must be pure because it boiled over a narrow range.
Give one reason why the student is wrong.
40 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.