Alkanes

• Crude oil is heated and vaporised before being fed into a fractionating column

  Vapours rise and condense into different fractions depending on their boiling points

  Lighter hydrocarbons at the top- low melting and boiling point

  Heavier chain hydrocarbons at the bottom - high melting and boiling points
• Cracking is the process of breaking down long chain hydrocarbons into higher demand shorter chain alkanes and alkenes
• Complete combustion produces CO2 and water

  releases CO2 which can cause global warming

  Incomplete combustion produced CO and water
• Incomplete combustion produces Carbon monoxide, the Carbon particulates are toxic and may cause respiratory problems

  Can also contribute to global dimming
• Incomplete combustion leads to the rise of dangerous pollutants such as nitrogen oxides

  N2+O2 = 2NO
• Catalytic convertors:

  Catalyst used in catalytic convertors is rhodium/platinum

  2 NO = N2 + O2

  2 NO + 2 CO = 2 CO2 + N2
• Combustion of hydrocarbons containing sulphur leads to acid rain

  Sulphur dioxide dissolves in rainwater and causes acid rain.

  S + O2 = SO2

  SO2 + H2O + 1/2 O2 = H2SO4
• Cracking:

  Thermal cracking - Hot temperature and high pressure and produces a high percentage of alkenes

  Catalytic cracking - high temperature and presence of a zeolite catalyst
• Flue gas desulfurization

  Sulphur can be removed from flu gases using:

  Caclium Oxide CaO

  SO2 + CaO = CaSO3