Combustion Reactions — The Chemistry of Fire
22 reacciones
Combustion is a rapid, exothermic reaction between a substance (the fuel) and an oxidant, usually oxygen, producing heat and light. Complete combustion of hydrocarbons yields carbon dioxide and water; incomplete combustion produces carbon monoxide or soot (elemental carbon). Combustion has powered human civilization since the mastery of fire over a million years ago and remains the primary energy source globally, generating approximately 80 percent of the world's energy.
Mecanismo de reacción
Combustion proceeds through a radical chain mechanism with three stages: initiation (heat breaks bonds to create free radicals), propagation (radicals react with fuel and oxygen to create more radicals and products), and termination (radicals combine to form stable products). The flame is a self-sustaining reaction zone where these steps occur simultaneously. The fire triangle — fuel, oxygen, and heat — must all be present; removing any one extinguishes the flame.
Ejemplos cotidianos
A gas stove burns methane: CH4 + 2O2 -> CO2 + 2H2O, releasing 890 kJ/mol. Automobile engines combust gasoline (octane: 2C8H18 + 25O2 -> 16CO2 + 18H2O). A candle's wax vaporizes and burns in the flame zone. Even our bodies perform slow combustion — cellular respiration oxidizes glucose to produce ATP energy, carbon dioxide, and water.
Importancia industrial
Fossil fuel combustion generates 36 billion tonnes of CO2 annually, making combustion chemistry central to the climate change discussion. Power plants burn coal, natural gas, or oil to generate electricity. Rocket engines use controlled combustion — the Space Shuttle main engines burned hydrogen and oxygen, producing only water vapor as exhaust. Steel production requires coke combustion in blast furnaces reaching 2,300 degrees C.
Safety Note
Incomplete combustion produces deadly carbon monoxide (CO), an odorless gas that causes roughly 400 deaths per year in the United States alone. Ensure proper ventilation for all combustion processes. Flammable vapor/air mixtures can explode — never use open flames near volatile organic solvents.
Combustión de acetileno
2C₂H₂ + 5O₂ → 4CO₂ + 2H₂O
Acetylene burns in oxygen with an intensely hot flame reaching 3300 C, the hottest of any common fuel-oxygen combination. The …
Combustión de benceno
2C₆H₆ + 15O₂ → 12CO₂ + 6H₂O
Benzene burns with a very smoky, sooty flame due to its high carbon-to-hydrogen ratio. The aromatic ring structure makes benzene …
Combustión de butano
2C₄H₁₀ + 13O₂ → 8CO₂ + 10H₂O
Butane burns in oxygen to produce carbon dioxide and water. Butane is the primary fuel in disposable cigarette lighters and …
Combustión de ciclohexano
C₆H₁₂ + 9O₂ → 6CO₂ + 6H₂O
Cyclohexane burns in oxygen to produce carbon dioxide and water. As a cycloalkane, cyclohexane has slightly different combustion characteristics than …
Combustión de etano
2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O
Ethane burns in oxygen to produce carbon dioxide and water. Ethane is the second most abundant component of natural gas …
Combustión de etanol
C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O
Ethanol burns in oxygen to produce carbon dioxide and water. Ethanol burns with a nearly invisible blue flame. As a …
Combustión de etileno
C₂H₄ + 3O₂ → 2CO₂ + 2H₂O
Ethylene burns in air with a luminous flame to form carbon dioxide and water. While ethylene can be burned as …
Combustión de fenol
2C₆H₅OH + 14O₂ → 12CO₂ + 6H₂O
Phenol burns in air with a very sooty flame due to its aromatic ring structure and high carbon content. Complete …
Combustión de glicerol
2C₃H₈O₃ + 7O₂ → 6CO₂ + 8H₂O
Glycerol (glycerin) burns in oxygen to produce carbon dioxide and water. As a byproduct of biodiesel production, excess glycerol is …
Combustión de glucosa (respiración celular)
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O
The overall equation for cellular respiration is chemically identical to glucose combustion. In living cells, this reaction occurs through many …
Combustión de hexano
2C₆H₁₄ + 19O₂ → 12CO₂ + 14H₂O
Hexane burns in oxygen to produce carbon dioxide and water. Hexane is a highly flammable alkane commonly used as a …
Combustión de hidrógeno gaseoso
2H₂ + O₂ → 2H₂O
Hydrogen gas burns in oxygen to produce water with no carbon-containing products. This makes hydrogen the ultimate clean fuel. The …
Combustión de isopropanol
2C₃H₇OH + 9O₂ → 6CO₂ + 8H₂O
Isopropanol (rubbing alcohol) burns in air with a yellow flame to produce carbon dioxide and water. Isopropanol is very flammable …
Combustión de metano
CH₄ + 2O₂ → CO₂ + 2H₂O
Methane burns in oxygen to produce carbon dioxide and water. This is the primary reaction in natural gas combustion, releasing …
Combustión de metanol
2CH₃OH + 3O₂ → 2CO₂ + 4H₂O
Methanol burns in air with a nearly invisible pale blue flame, making methanol fires extremely dangerous because they are hard …
Combustión de monóxido de carbono
2CO + O₂ → 2CO₂
Carbon monoxide burns in air with a characteristic blue flame to produce carbon dioxide. This reaction completes the oxidation of …
Combustión de naftaleno
C₁₀H₈ + 12O₂ → 10CO₂ + 4H₂O
Naphthalene burns with a very smoky, luminous flame characteristic of polycyclic aromatic hydrocarbons. Its high carbon content results in significant …
Combustión de octano (gasolina)
2C₈H₁₈ + 25O₂ → 16CO₂ + 18H₂O
Octane, a major component of gasoline, burns in oxygen to produce carbon dioxide and water. This reaction powers internal combustion …
Combustión de propano
C₃H₈ + 5O₂ → 3CO₂ + 4H₂O
Propane combusts in oxygen to produce carbon dioxide and water. Propane is a widely used fuel gas stored as a …
Combustión de sacarosa
C₁₂H₂₂O₁₁ + 12O₂ → 12CO₂ + 11H₂O
Sucrose (table sugar) burns in oxygen to produce carbon dioxide and water. When ignited directly, sugar burns slowly. However, when …
Combustión de xileno
C₈H₁₀ + 10.5O₂ → 8CO₂ + 5H₂O
Xylene (dimethylbenzene) burns with a smoky yellow flame. Xylene exists as three isomers (ortho, meta, para), all with similar combustion …
Combustión incompleta del metano
2CH₄ + 3O₂ → 2CO + 4H₂O
When methane burns in insufficient oxygen, carbon monoxide forms instead of carbon dioxide. This incomplete combustion is dangerous because CO …