Saturated & Unsaturated Compounds (Cambridge (CIE) O Level Chemistry): Revision Note

Saturated & Unsaturated Compounds

Alkanes

• Saturated compounds have molecules in which all carbon-carbon bonds are single bonds 

• Examples of compounds that are saturated are alkanes 

• Alkanes are saturated hydrocarbons with the general formula C_nH_2n+2

Methane

• Molecular formula: CH₄

• Displayed formula:

Ethane

• Molecular formula: C₂H₆

• Displayed formula:

Propane

• Molecular formula: C₃H₈

• Displayed formula:

Alkenes

• Unsaturated compounds consist of molecules in which one or more carbon-carbon bonds are not single bonds

• They contain carbon-carbon double bonds (C=C)

• Examples of compounds that are unsaturated are alkenes

• Alkenes are unsaturated hydrocarbons with the general formula C_nH_2n

• The presence of the double bond, C=C, means they can make more bonds with other atoms by opening up the C=C bond and allowing incoming atoms to form another single bond with each carbon atom of the functional group

• Each of these carbon atoms now forms 4 single bonds instead of 1 double and 2 single bonds

Ethene

• Molecular formula: C₂H₄

• Displayed formula:

Propene

• Molecular formula: C₃H₆

• Displayed formula:

But-1-ene

• Molecular formula: C₄H₈

• Displayed formula: