A cosmetics company measures the temperature range over which two batches of a solid lip balm melt.
| Batch | Melting range |
|---|---|
| A | 58 ∘C58\,^{\circ}\mathrm{C}58∘C to 63 ∘C63\,^{\circ}\mathrm{C}63∘C |
| B | 59 ∘C59\,^{\circ}\mathrm{C}59∘C to 64 ∘C64\,^{\circ}\mathrm{C}64∘C |
Both batches were made to the same recipe.
Which conclusion is best supported by the results?
Each batch is a mixture, and the similar ranges show that the recipe gives consistent batches.
Each batch melts over a range because its ingredients have reacted to form new compounds.
Batch B is pure and batch A is impure, because batch B melts at higher temperatures.
Each batch is a single pure substance, because it was made to a fixed recipe.
102 exam-style questions on OCR GCSE Chemistry 2.1 Purity and separating mixtures, covering 2.1.1 Pure substances and melting point data, 2.1.2 Relative formula mass and empirical formula, 2.1.3 Formulations as useful mixtures, 2.1.4 Techniques for separating mixtures, and 2.1.5 Chromatography and Rf values. Each one has a worked solution and a mark scheme showing where the marks go.