Combustion is the chemical chain reaction that feeds a fire more heat and allows it to continue. With most types of fires, the old fire triangle model works well enough, but when the fire involves burning metals, such as magnesium and lithium, it becomes useful to consider the chemistry of combustion. Putting water on such a fire could increase the heat of the fire and could be the catalyst for an explosion. In this type of fire, specialised chemicals must be used to break the chain reaction of metallic combustion, therefore extinguishing the fire. Complete combustion reactions need a plentiful supply of air so that the elements in the fuel react fully with oxygen. Fuels such as natural gas and petrol contain hydrocarbons. These are compounds of hydrogen and carbon only. Incomplete combustion reactions occur when the supply of air or oxygen is poor. Water is still produced, but carbon monoxide and carbon are produced instead of carbon dioxide. Combustion Combustion is a chemical reaction that occurs between a fuel and an oxidiser, typically in the form of oxygen gas (O 2 ). It is a rapid exothermic (heat-releasing) reaction that produces flames, heat, and light. Combustion is an essential process in many everyday applications, such as burning fuels for heating, cooking, and transportation. Note that in addition to oxygen (O 2 ), chemicals such as hydrogen peroxide (H 2 O 2 ), nitric acid (HNO 3 ) and potassium nitrate (KNO 3 ) are typical oxidising agents. The combustion reaction involving nitric acid is highly exothermic, and can be represented as follows: 4 HNO 3 + 5 O 2 → 4 NO 2 (nitrogen dioxide) + 6 H 2 O 2 During combustion, the fuel undergoes oxidation, where it reacts with oxygen to produce energy in the form of heat and light. The fuel and oxygen molecules break apart, rearrange, and form new molecules. The reaction products of combustion typically include carbon dioxide (CO 2 ), water vapour (H 2 O), and other combustion byproducts such as carbon monoxide (CO), nitrogen oxides (NO X ), and particulate matter. The reaction can be represented by a chemical equation, where a typical hydrocarbon fuel like methane (CH 4 ) reacts with oxygen: CH 4 (methane) + 2 O 2 (oxygen) -> CO 2 (carbon dioxide) + 2 H 2 O (water vapour) + energy The release of energy in the form of heat and light is what makes combustion useful for various applications. The energy generated during combustion can be harnessed for heating, electricity generation,
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