triple

• corrosion - metal broken down by oxygen
• rust - iron broken down by oxygen and water
• preventing rusting

  • barrier method
  • sacrificial method
• barriers against rusting

  • greasing
  • painting
  • electroplating - coat iron in another metal that won't corrode
• sacrificial method against rusting

  • add a block of more reactive metal to iron
  • water / oxygen react with the sacrificial metal first instead of the iron
• Titration

  • find an unknown concentration of acid / alkali
  • pipette - measure 25 cm of alkali and add to conical flask with methyl orange
  • buirette - fill with acid
  • use the tap to add precise volume of acid to alkali
  • starts - yellow in alkali
  • turns orange when neutralised
• atom economy

  MR of desired product / MR of all reactants X 100
• low atom economy

  • expensive
  • less sustainable
  • more waste product
• percentage yield

  actual yield / theoretical yield X 100
• less than 100 % percentage yield

  • side reactions
  • gasses escape
  • reactants not fully used up
• Harbour process

  N$N_2+$$3NH_3\leftrightarrow2NH_3$
• harbour process conditions

  • 450 C
  • 200 atmospheres
  • iron catalysts
• harbour process

  • nitrogen - taken from the air
  • hydrogen - taken from natural gas
• fertiliser

  • supply plants with nutrients
  • contains - nitrogen, phosphorus, potassium
• hydrogen / oxygen fuel cells

  • hydrogen - loses electrons / move to cathode
  • oxygen - gains electrons at cathode