A manufacturer is developing a scented room spray.
One fragrance ingredient has an accepted boiling point of 176 ∘C176\ ^\circ\text{C}176 ∘C. A sample of the ingredient was heated and its boiling temperatures were recorded.
| Measurement | Temperature in ∘C^\circ\text{C}∘C |
|---|---|
| Boiling started | 169 |
| Boiling finished | 173 |
Three trial recipes are prepared by measuring and mixing fragrance, solvent and water. Each recipe makes 100 cm3 of spray. The results are shown in the table.
| Recipe | Volume of fragrance in cm3\text{cm}^3cm3 | Drying time in seconds |
|---|---|---|
| P | 8 | 31 |
| Q | 12 | 39 |
| R | 15 | 54 |
The room spray must contain at least 10 cm3 of fragrance in every 100 cm3 of spray and must dry in under 45 seconds.
Explain whether the sample of the fragrance ingredient is pure.
Which recipe should the manufacturer use?
Give a reason for your answer.
Another batch is made using the same three components, but the quantities of the components are not measured.
Explain why this batch might not meet the manufacturer's requirements.
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.