Hydrocarbons

Hydrocarbons - organic compounds of only carbon and hydrogen

Simplest class of organic compounds

commonly used as fuels e.g methane, propane, octance

Classifications of hydrocarbons

• Aliphatic hydrocarbons

  • Alkanes - saturated, single bond only

  • Alkenes - unsaturated, one or more double bonds

  • Alkynes unsaturated one or more triple bond

• Aromatic hydrocarbons

  • Contain benzene (delocalised electrons)

Homologous series

• same general formula

• similar chemical properties

• Gradual changes in physical properties e.g boiling point

• each member differs by CH2 unut

Example - Alkane: CH4, C2H6, C3H8, C4H10

Trends in physical properties

Boiling metling pounds increase with molecular size

Straight chain hydrocarbons have higher boiling points than branched ones (due to surface area

Aormatic hydrocarbons tend to have higher boiling points than aliphatic hydrocarbons of similar size → because of delocalised electrons

Uses of hydrocarbon

Fuel

Solvents

Plastics: ethene (polyethylene), propene

Pharmaceuticals and dyes (Aromatic hydrocarbons