making fertilisers

• • fertilisers are made in the laboratory or industrially
• industrial method:

  • temp - 60-450 degrees
  • equipment - very expensive machinery
  • reactants - raw materials e.g sulfur, air, water
  • scale - makes large quantity
  • running costs - automatic which reduces labour and running costs
  • process - exothermic, heat released used to evaporate water = very concentrated product
• laboratory method:

  • temp - room temp for neutralisation, heating to evaporate water
  • equipment - cheap and versatile machinery
  • reactants - chemical supplier
  • scale - small quantity slowly
  • running costs - labour intensive, high running costs
• • reactants in the laboratory are in a lower concentration than the industry
  • so, less heat is produced so it is safer to be carried out
• • crystallisation is used in the laboratory
  • it is not used in industry because it is very slow
• making ammonium salts:

  1. 25cm of ammonia solution measured with cylinder, poured into conical flask
  2. two drops of methyl orange indicator, will turn yellow
  3. dilute acid added from burette slowly until methyl orange turns orange
  4. record volume of acid added, neutral solution of ammonium salt thrown away
  5. experiment repeated without indicator but with same volumes of ammonia and acid
  6. ammonium salt crystallised by evaporating water and drying cystals