C12

• sulphur - the element
  • yellow non-metallic element
  • found in group VI
  • brittle, non-conducting, solid, low melting point (115°C)
  • doesn't dissolve in water but in carbon disulphide and methylbenzene (toluene)
  • it has allotropes:
    • rhombic sulphur
    • monoclinic sulphur
  • uses of sulphur:
    • vulcanise rubber (make rubber harder and increase elasticity)
    • to manufacture matches, fireworks, fungicides, as a sterilising agent and in medicine
    • most important use is for sulphuric acid
• Sulphuric acid
  • the process by which sulphuric acid is produced is called the contact process
  • Sulphur dioxide is produced by the reaction of sulfur with air:
    • sulphur + oxygen → sulfure dioxide
  • dust and impurities are removed from it as well as any unreactive oxygen.
  • these clean gases are heated to a temperature of around 450°C and fed into a reaction vessel where they are passed over a catalyst of vanadium oxide
  • this catalyses the reaction between sulfur dioxide and oxygen to produce sulfur trioxide:
    • sulfur dioxide + oxygen → sulfur trioxide
  • this reaction is reversible
  • 96% of the sulfur dioxide snd oxygen are converted into sulfur trioxide
  • if sulphuric trioxide is added directly to water it creates sulphuric acid. this reaction however is very violent and creates thick mist
  • this is very difficult to deal with so sulfur trioxide is dissolved in a concentrated sulphuric acid (98%) to give a substance called oleum instead.
  • the oleum is then added to the correct amount of water to produce sulphuric acid

use of sulphuric acid:

• • steel manufacture
  • plastics
  • metal salts
  • fertilisers
  • chemicals
  • paint and pigments
  • detergent
  • artificial fibres