- published: 14 Aug 2015
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Combustion /kəmˈbʌs.tʃən/ or burning is a high-temperature exothermic redox chemical reaction between a fuel and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combustion in a fire produces a flame, and the heat produced can make combustion self-sustaining. Combustion is often a complicated sequence of elementary radical reactions. Solid fuels, such as wood, first undergo endothermic pyrolysis to produce gaseous fuels whose combustion then supplies the heat required to produce more of them. Combustion is often hot enough that light in the form of either glowing or a flame is produced. A simple example can be seen in the combustion of hydrogen and oxygen into water vapor, a reaction commonly used to fuel rocket engines. This reaction releases 242 kJ/mol of heat and reduces the enthalpy accordingly (at constant temperature and pressure):
Combustion of an organic fuel in air is always exothermic because the double bond in O2 is much weaker than other double bonds or pairs of single bonds, and therefore the formation of the stronger bonds in the combustion products CO2 and H2O results in the release of energy. The bond energies in the fuel play only a minor role, since they are similar to those in the combustion products; e.g., the sum of the bond energies of CH4 is nearly the same as that of CO2. The heat of combustion is approximately -418 kJ per mole of O2 used up in the combustion reaction, and can be estimated from the elemental composition of the fuel.
No more ifs, no bias, no ambiguity
No wondering whether this is it
Clarity, so brightly shining
The image so painfully absolute
No edges blurred on this awareness
No unknown weight to tip the knowledge scales
Eyes dilated to grasp it all
As every illusion of what we are fails
An unquestionable picture, determined, complete
Its crystalline lines untouched by doubt
So vivid, so deprived of hesitation
Shining in its evil splendor
The burning hatred of man
A million degrees on display
Human voracity delineated
The demons in us all by fumes portrayed
Stare, see, take in, grasp
Comprehend, assimilate
Behold your reflection
The framing gold plated lies
The canvas hurting souls caught and weaved
The artist, the human dream