Alkane

Key Stage 4

Meaning

Alkanes are the simplest form of hydrocarbon compounds with no double bonds and the general formula; C_nH_2n+2

About Alkanes

Alkanes are a homologous series of hydrocarbon compounds.

The functional group of the Alkanes is the single bonds between the Carbon atoms and between the Carbon and Hydrogen atoms.

Alkanes are long chains of Carbon atoms covalently bonded together with single bonds and Hydrogen atoms taking the remaining bonds.

Examples

	Methane	Ethane	Propane	Butane
Chemical Formula (CnH2n+2)	CH4	C2H6	C3H8	C4H10
Structural Formula	CH4	CH3CH3	CH3CH2CH3	CH3CH2CH2CH3
Structural Diagram
Ball and Stick Model

Reactions of Alkanes

Combustion

During combustion of alkanes the Carbon and Hydrogen atoms are oxidised to produce Carbon Dioxide and Water.

Complete Combustion

Complete combustion occurs when there is enough Oxygen to completely Oxidise all of the atoms in the alkane. In the complete combustion of alkanes the only products are Carbon Dioxide and Water.

Methane + Oxygen → Carbon Dioxide + Water

<chem>CH4 + 2O2 -> CO2 + 2H2O</chem>

Ethane + Oxygen → Carbon Dioxide + Water

<chem>2C2H6 + 7O2 -> 4CO2 + 6H2O</chem>

Propane + Oxygen → Carbon Dioxide + Water

<chem>C3H8 + 5O2 -> 3CO2 + 4H2O</chem>

Butane + Oxygen → Carbon Dioxide + Water

<chem>2C4H10 + 13O2 -> 8CO2 + 10H2O</chem>

Incomplete Combustion

Incomplete combustion occurs when there is not enough Oxygen to Oxidise all of the atoms in the alkane. During incomplete combustion of alkanes the products may include Carbon (soot) and Carbon Monoxide.

Methane + Oxygen → Carbon + Water

<chem>CH4 + O2 -> C + 2H2O</chem>

Methane + Oxygen → Carbon Monoxide + Water

<chem>CH4 + 1.5O2 -> CO + 2H2O</chem>

Ethane + Oxygen → Carbon Dioxide + Water

<chem>2C2H6 + 7O2 -> 4CO2 + 6H2O</chem>

Propane + Oxygen → Carbon Dioxide + Water

<chem>C3H8 + 5O2 -> 3CO2 + 4H2O</chem>

Butane + Oxygen → Carbon Dioxide + Water

<chem>2C4H10 + 13O2 -> 8CO2 + 10H2O</chem>