Edexcel iGCSE Chemistry -4.9 Uses of Fractions from Crude Oil- Study Notes- New Syllabus
Edexcel iGCSE Chemistry -4.9 Uses of Fractions from Crude Oil- Study Notes- New syllabus
Edexcel iGCSE Chemistry -4.9 Uses of Fractions from Crude Oil- Study Notes -Edexcel iGCSE Chemistry – per latest Syllabus.
Key Concepts:
4.9 know the names and uses of the main fractions obtained from crude oil:
refinery gases, gasoline, kerosene, diesel, fuel oil and bitumen
4.9 Main Fractions from Crude Oil: Names and Uses
Crude oil is separated by fractional distillation into fractions.
Each fraction:
- Contains hydrocarbons with similar chain lengths.
- Has a similar boiling point range.
- Has specific uses.
Main Fractions and Their Uses
| Fraction | Boiling Point | Uses |
|---|---|---|
| Refinery gases | Lowest | Heating and cooking fuel (LPG) |
| Gasoline (Petrol) | Low | Fuel for cars |
| Kerosene | Medium | Jet fuel, heating fuel |
| Diesel | High | Fuel for buses, lorries and some cars |
| Fuel oil | Very high | Fuel for ships and power stations |
| Bitumen | Highest | Road surfacing and roofing |
Trends in the Fractions
- Going down the column → boiling point increases.
- Chain length increases.
- Viscosity increases.
- Flammability decreases.
Exam Focus
Students must know:
- The names of these six main fractions.
- One typical use for each.
- That they are separated based on boiling point.
Example 1 (Conceptual):
Why is bitumen collected at the bottom of the fractionating column?
▶️ Answer/Explanation
It contains very long hydrocarbon chains.
It has a very high boiling point.
It condenses at high temperatures near the bottom.
Example 2 (Application):
Which fraction is most suitable as fuel for aeroplanes?
▶️ Answer/Explanation
Kerosene.
It is commonly used as jet fuel.
Example 3 (Hard ):
Explain fully why refinery gases are collected at the top of the fractionating column and used as fuels.
▶️ Answer/Explanation
Refinery gases contain very small hydrocarbon molecules.
They have low boiling points.
They do not condense until they reach the coolest part of the column.
Therefore they are collected at the top.
They are highly flammable.
This makes them suitable for heating and cooking.