3.3.2.3. combustion of alkanes

• why do alkanes make good fuels?

  release a lot of energy when burned
• complete combustion 


  with sufficient oxygen, alkanes undergo complete combustion to produce CO2 and water
• complete combustion equation 


  CH4 + 2 O2 -> CO2 + 2 H2O
• incomplete combustion equation 


  2 CH4 + 3 O2 -> 2 CO + 4 H2O
• carbon monoxide


  toxic gaseous product
• why is carbon monoxide especially dangerous to humans?

  no odour or colour
• what are produced as a byproduct of alkane combustion?

  oxides of nitrogen
• how can both of these gaseous produces be removed from systems?

  using a catalytic converter
• what does a catalytic converter do?

  uses a rhodium catalyst to convert harmful products into more stable products e.g. CO2 or H2O
• catalytic converter

  
• what can incomplete combustion produce?

  carbon particulates, small fragments of unburned hydrocarbons
• what can the carbon particulates cause, unless removed?

  serious respiratory problems - pollute the air
• what can sulphur impurities lead to?

  acidification of water in the Earth's atmosphere - react to form a weak form of H2SO4
• how can the sulphur impurities be removed from waste products?

  via flue gas desulphurisation
• what's used in the flue gas desulphurisation process?

  calcium oxide and gypsum
• what will happen if it isn't treated?

  all of these pollutants can contribute to global warming, acid rain and health issues in humans