Notes on Fossil Fuels and Fractional Distillation

Definition of a Fuel: A substance that can be burned to produce energy, primarily in the form of heat.

Fossil Fuels: Energy-rich substances derived from ancient plants and animals, formed over millions of years through heat and pressure.
Common Fossil Fuels:
- Coal: Solid fossil fuel made from ancient plant remains, used for electricity and heating.
- Natural Gas: Mainly composed of methane (CH₄); used for heating, cooking, and electricity generation.
- Petroleum (Crude Oil): A liquid mixture of hydrocarbons. Must be refined to produce usable products.

Definition: Compounds made up of hydrogen and carbon only. Example: Alkanes.

Process Overview: The separation of petroleum into fractions based on boiling points.
Method:
- Heated in a fractionating column.
- Smaller molecules evaporate and rise, while larger ones condense at lower levels.

Key Changes from Bottom to Top:
1. Decreasing Chain Length: Longer carbon chains at the bottom, shorter at the top.
2. Higher Volatility: Lighter fractions at the top evaporate more easily.
3. Lower Boiling Points: Hydrocarbons at top condense at lower temperatures.
4. Lower Viscosity: Fractions at top are less viscous (runnier).
Molecular Size Impact: Larger molecules have higher boiling points and lower volatility; smaller molecules are more volatile and have lower boiling points.

As you move up the fractionating column:
- Chain Length: Decreases
- Volatility: Increases
- Boiling Point: Decreases
- Viscosity: Decreases

Refinery Gas: Fuel for heating and cooking.
Gasoline (Petrol): Fuel for cars.
Naphtha: Used as a chemical feedstock (raw materials for chemicals, plastics).
Kerosene (Paraffin): Jet fuel.
Diesel Oil (Gas Oil): Fuel for diesel engines.
Fuel Oil: Used in ships and heating systems.
Lubricating Oil: For lubricants, waxes, and polishers.
Bitumen: For making roads.