* Fossil fuel itself: This could be coal, oil, or natural gas. The specific chemical composition of the fuel will vary depending on the type, but it generally consists of hydrocarbons (molecules made up of carbon and hydrogen).

* Oxygen: This is essential for combustion to occur. Oxygen is readily available in the air.

Simplified Chemical Equation:

The combustion of fossil fuels can be represented by a simplified chemical equation:

Fuel + Oxygen → Carbon Dioxide + Water + Energy

More Detailed Example (for burning methane, a component of natural gas):

CH₄ + 2O₂ → CO₂ + 2H₂O + Energy

This equation shows that when methane (CH₄) reacts with oxygen (O₂), it produces carbon dioxide (CO₂), water (H₂O), and releases energy in the form of heat and light.