Alkanes (CIE IGCSE Chemistry: Co-ordinated Sciences (Double Award))

• Alkanes are a group of saturated hydrocarbons
• The term saturated means that they only have single carbon-carbon bonds, there are no double bonds
• Alkanes have covalent bonds as they consist of non-metal atoms 
• 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 in substitution reactions

• Methane undergoes complete combustion forming carbon dioxide and water:

CH₄ (g) + 2O₂ (g) → CO₂ (g) + 2H₂O (l)

Table of alkanes

Displayed formula	Name	Molecular formula
	methane	CH4
	ethane	C2H6
	propane	C3H8
	butane	C4H10
	pentane	C5H12

The first five members of the alkane homologous series