An engineer is choosing collection positions for two hydrocarbons in a fractionating column. A liquid mixture of the hydrocarbons is heated to 210 °C and enters the column at position X. The hydrocarbons then move upwards towards position Y.
| Hydrocarbon | Boiling point |
|---|---|
| R | 85 °C |
| S | 165 °C |
| Position in the column | Temperature |
|---|---|
| X, lower in the column | 210 °C |
| Y, higher in the column | 115 °C |
The temperature continues to decrease above position Y.
Use the data to describe the changes of state of each hydrocarbon from heating to position Y. Explain how this separates the hydrocarbons and predict where hydrocarbon R should be collected.
91 exam-style questions on AQA GCSE Chemistry 7.1 Carbon compounds as fuels and feedstock, covering 7.1.1 Crude oil, hydrocarbons and alkanes, 7.1.2 Fractional distillation and petrochemicals, 7.1.3 Properties of hydrocarbons, and 7.1.4 Cracking and alkenes. Each one has a worked solution and a mark scheme showing where the marks go.