Fractional Distillation

IGCSE Edexcel Chemistry
4.8-4.10 Fractional distillation of crude oil
Key Concept: Crude oil is separated by boiling point. Fractions with lower boiling points are collected near the top of the column.

Section A: Process

1. Describe how fractional distillation separates crude oil. [3]
2. State the trend in boiling point and viscosity from top to bottom of the column. [2]

Section B: Fractions

3. Name three fractions and one use for each. [3]

Total marks: 8

Mark Scheme

1. Heat crude oil to vaporize; vapors rise and cool; different boiling points condense at different heights [3]
2. Boiling point and viscosity increase down the column [2]
3. Any three with uses: refinery gas (LPG), gasoline (car fuel), kerosene (jet fuel), diesel (cars), fuel oil (ships), bitumen (roads) [3]