In chemistry, a hydrocarbon is an organic compound consisting only of carbon and hydrogen. They all consist a carbon backbone and atoms of hydrogen attached to that backbone, also aliphatic hydrocarbons.
For example, methane (swamp gas) is a hydrocarbon with one carbon atom and four hydrogen atoms: CH4, ethane is a hydrocarbon (more specifically, an alkane) consisting of two carbon atoms held together with a single bond, each with three hydrogen atoms bonded C2H6, propane has three C atoms (C3H8) and so on (CnH2·n+2).
There are basically three types of hydrocarbons:
- aromatic hydrocarbons, which have at least one aromatic ring in addition to whatever bonds they have
- saturated hydrocarbons (Also known as alkanes), which don't have double, triple or aromatic bonds
- unsaturated hydrocarbons, which have one or more double or triple bonds between carbon atoms. Unsaturated hydrocarbons are divided into:
The number of hydrogen atoms in Hydrocarbons can be determined, if the number of carbon atoms is known, by using these equations:
- Alkanes: CnH2n+2
- Alkenes: CnH2n
- Alkynes: CnH2n-2
Liquid geologically-extracted hydrocarbons are referred to as petroleum (literally "rock oil") or mineral oil, while gaseous geologic hydrocarbons are referred to as natural gas. All are significant sources of fuel and raw materials as a feedstock for the production of organic chemicals and are commonly found in the subsurface using the tools of petroleum geology.
Hydrocarbons are of prime economic importance because they encompass the constituents of the major fossil fuels (coal,petroleum, natural gas, etc.) and biofuels, as well as plastics, waxes, and oils. In urban pollution, these components--along with NOx and sunlight--all contribute to the formation of tropospheric ozone.