Carbon and virtually all substances containing carbon, particularly hydrocarbons, are the primary materials that burn in the presence of sufficient oxygen to produce carbon dioxide (CO2). This fundamental chemical reaction is known as combustion.
The Role of Carbon in Combustion
Combustion is a high-temperature exothermic (heat-releasing) redox chemical reaction between a fuel and an oxidant, usually atmospheric oxygen, that produces oxidized gaseous products. When carbon is present in the fuel, it readily combines with oxygen to form carbon dioxide.
Even pure forms of carbon, such as graphite and diamond, will burn in oxygen to yield carbon dioxide, demonstrating carbon's fundamental role in this reaction. For example:
- Carbon (solid) + Oxygen (gas) → Carbon Dioxide (gas)
- C (s) + O2 (g) → CO2 (g)
Common Carbon-Containing Fuels
Most of the fuels we use daily are rich in carbon and hydrogen. When these substances burn, the carbon atoms combine with oxygen to form CO2, and hydrogen atoms combine with oxygen to form water (H2O).
Here are some common examples of substances that produce carbon dioxide when they burn:
- Fossil Fuels: These are geological deposits of organic materials formed from dead plants and animals that have been converted into crude oil, coal, natural gas, or heavy oils over millions of years.
- Coal: Primarily composed of carbon, it releases a significant amount of CO2 upon combustion.
- Natural Gas: Mainly methane (CH4), its combustion produces CO2 and water.
- Petroleum (Oil): A complex mixture of various hydrocarbons, gasoline, diesel, and heating oil derived from petroleum all produce CO2 when burned in engines or furnaces.
- Biomass: Organic matter used as a fuel, especially in a power station for the generation of electricity.
- Wood: Composed of cellulose and lignin (carbon, hydrogen, oxygen), wood burning produces CO2, water, and other byproducts.
- Ethanol: (C2H5OH), a common biofuel, burns to produce CO2 and water.
- Other Hydrocarbons:
- Propane and Butane: Used in gas grills and lighters, these also release CO2.
- Plastics: Many plastics are derived from petroleum and release CO2 when incinerated.
- Candle Wax: Predominantly long-chain hydrocarbons, wax combustion also yields carbon dioxide.
Examples of Substances and Their Emissions
| Substance | Primary Elements | Carbon Dioxide Production | Common Use Case |
|---|---|---|---|
| Graphite | Carbon | High | Industrial electrodes |
| Diamond | Carbon | High | Gemstones, industrial tools |
| Natural Gas | Carbon, Hydrogen | High | Heating, electricity generation |
| Gasoline | Carbon, Hydrogen | High | Vehicle fuel |
| Coal | Carbon | High | Electricity generation, industrial heat |
| Wood | Carbon, Hydrogen, Oxygen | High | Heating, cooking |
| Propane | Carbon, Hydrogen | High | Grilling, portable heating |
| Candle Wax | Carbon, Hydrogen | High | Lighting, ambiance |
Understanding what burns to produce carbon dioxide is crucial for comprehending energy production, atmospheric chemistry, and the impacts of human activities on the environment.
