Hydrocarbons

Hydrocarbons only contain hydrogen and carbon atoms

• A hydrocarbon is any compound that is formed from carbon and hydrogen atoms only
• So C10H22 is a hydrocarbons, but CO2 isn’t because it contains oxygen

Alkanes have all C-C single bonds

• Alkanes are the simplest type of hydrocarbon you can get
  • They have the general formula CnH2n+2
  • The alkanes are a homologous series, a group of organic compounds that react in a similar way
  • Alkanes are saturated compounds, each carbon atoms forms four single covalent bonds
  • The first four alkanes are methane, ethane, propane, butane

Hydrocarbon properties change as the chain gets longer

• The shorter the carbon chain the…
  • Less viscous
  • More volatile
  • More flammable
  • Lower boiling point
• The longer the carbon chain is…
  • More viscous
  • Less volatile
  • Less flammable
  • Higher boiling point

Complete combustion occurs when there’s plenty of oxygen

• The complete combustion in oxygen release lots of energy

• Waste products are carbon dioxide and water vapour

  • Hydrocarbon + oxygen - Carbon dioxide + water

• During combustion, both hydrogen and carbon is oxidised

• Hydrocarbons are used as fuels due to the large amount of energy released