Alkanes (Edexcel GCSE Chemistry): Revision Note

Alkanes

• Alkanes are a group of saturated hydrocarbons

  • The term saturated means that they only have single carbon-carbon bonds, there are no double bonds

• The general formula of the alkanes is C_nH_2n+2

• They are colourless compounds which have a gradual change in their physical properties as the number of carbon atoms in the chain increases

• Alkanes are generally unreactive compounds but they do undergo combustion reactions, can be cracked into smaller molecules and can react with halogens in the presence of light

• Methane is an alkane and is the major component of natural gas

The first four alkanes

• The first four members of the alkanes are:

• Methane

  • Molecular formula: CH₄

• Ethane

  • Molecular formula: C₂H₆

• Propane

  • Molecular formula: C₃H₈

• Butane

  • Molecular formula: C₄H₁₀