A occurs when a substance reacts with oxygen to produce energy in the form of heat and light.

The process you're describing is known as combustion. Combustion occurs when a fuel reacts with oxygen, leading to the release of energy, typically in the form of heat and light. There are two main types of combustion: complete and incomplete.

1. Complete Combustion: This occurs when there is a sufficient supply of oxygen. The products of complete combustion are usually carbon dioxide (CO₂) and water (H₂O). An example is the combustion of methane (CH₄) in the presence of enough oxygen:

   $CH_4 + 2O_2 \rightarrow CO_2 + 2H_2O + \text{energy}$

2. Incomplete Combustion: This happens when there is not enough oxygen available. This can result in the formation of carbon monoxide (CO) or soot (carbon particles) along with water, and it releases less energy than complete combustion:

   $2CH_4 + 3O_2 \rightarrow 2CO + 4H_2O + \text{energy}$

Combustion is an essential chemical reaction used in various applications, including engines, heating systems, and rockets. It’s important for industries, but it also contributes to air pollution if not controlled properly.