Chemical Reactivity

Organic - Alkanes

Combustion is the reaction of a molecule with oxygen. The alkanes are highly combustible and are valuable as clean fuels, burning to form water and carbon dioxide.1 This is significant because this is how we as a civilization have been heated since early history; it is a major source of energy (heat). This large outsource of heat is due to every bond in the alkane being broken to form carbon dioxide (CO2) and water (H2O). The energy created from the bonds being broken comes in the form of heat.2

Halogenation is the substitution of one or more hydrogens in a molecule with a halogen (fluorine, chlorine, bromine, iodine).2 Fluorine is generally very reactive, so isn’t safe to use for halogenation. Iodine, on the contrary, is too unresponsive usually. With chlorination or bromination (the often used halogens for this purpose), an input of energy in the form of heat or light is required to initiate the reaction.2

 

Real World Application

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Due to the value of using alkanes for combustion reations, there are many real life applications that have to do with fuel. For example, propane is used in petroleum gas. Pentane and octane are used in gasoline (internal combustion engines). Alkanes are also used in diesel fuel. There are also small amounts of alkanes used in aerosol spray products.2

Additionally, because alkanes are relatively easy to halogenate, they are used in synthetic reactions to create other molecules for scientific purposes.

 

Vocabulary

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 Important Vocabulary

Term Context
Combustion The reaction of a molecule with oxygen. The combustion of alkane produces carbon dioxide and water. 
Halogenation The substitution of one or more hydrogens in an alkane with a halogen (iodine, bromine, chlorine, fluorine)

 

Videos

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Alkane Combustion

Combustion of alkanes


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