Combustion ( /kəmˈbʌs.tʃən/) or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can produce light in the form of either glowing or a flame. Fuels of interest often include organic compounds (especially hydrocarbons) in the gas, liquid or solid phase.
In a complete combustion reaction, a compound reacts with an oxidizing element, such as oxygen or fluorine, and the products are compounds of each element in the fuel with the oxidizing element. For example:
- CH4 + 2 O2 → CO2 + 2 H2O + energy
A simple example can be seen in the combustion of hydrogen and oxygen, which is a commonly used reaction in rocket engines:
- 2 H2 + O2 → 2 H2O(g) + heat
The result is water vapor.
Complete combustion is almost impossible to achieve. In reality, as actual combustion reactions come to equilibrium, a wide variety of major and minor species will be present such as carbon monoxide and pure carbon (soot or ash). Additionally, any combustion in atmospheric air, which is 78 percent nitrogen, will also create several forms of nitrogen oxides.
Famous quotes containing the word combustion:
“The night has been unruly. Where we lay,
Our chimneys were blown down, and, as they say,
Lamentings heard i th air, strange screams of death,
And prophesying with accents terrible
Of dire combustion and confused events,
New-hatched to the woeful time.”
—William Shakespeare (15641616)
“Him the Almighty Power
Hurld headlong flaming from th Ethereal Skie
With hideous ruine and combustion down
To bottomless perdition, there to dwell
In Adamantine Chains and penal Fire,
Who durst defie th Omnipotent to Arms.
Nine times the Space that measures Day and Night
To mortal men, he with his horrid crew
Lay vanquisht, rowling in the fiery Gulfe”
—John Milton (16081674)