1. sulphur
   1. location
      1. underground beds
      2. metal ores
      3. oil
      4. natural gas
2. uses
   1. chemical industry
      1. manufacture of other chemicals
         1. fertilisers
         2. plastics
      2. dyes and other chemicals 9%
      3. plastics 9%
      4. cleaning metals for electroplating 3%
      5. detergents 10%
      6. paints 16%
      7. fibres 14%
      8. fertilisers 32%
3. CONTACT PROCESS
   1. sulphur dioxide oxidised to sulphur trioxide
   2. air used in
      1. sulphur dioxide
      2. sulphur trioxide
   3. stage1
      1. S (s) + O2 (g) ---> SO2 (g)
   4. stage2
      1. 2SO2(g) + O2 <--> 2SO3 (g)
         1. deltaH = -192 kJ mol-1
         2. reversable reaction
      2. contact process
   5. stage 3
      1. SO3 (g) + H2SO4 (l) (concentrated) ---> H2S2O7 (l) [oleum]
   6. stage 4
      1. H2S2O7 (l) [oleum] + H2O ---> 2H2SO4 (l) [sulphuric acid]
4. sulphur trioxide + water
   1. H2O(l) + SO2(g) ---> H2SO4 (l)
   2. seems simple
   3. very dangerous
      1. very exothermic
      2. "acid mist"
5. conditions for contact process
   1. low temperature
      1. greatest yield
         1. exothermic
      2. slow
   2. high pressure
      1. greater yield
      2. equipment costly
   3. compromise conditions
      1. 450C
      2. catalyst
         1. (instead of high pressure)
         2. increases rate NOT yield