Fertilisers (Haber Process)

• What are fertilisers essential for?

  Healthy growth of crops
• How can fertilisers be produced?

  In the laboratory and by the chemical industry
• What is ammonia used to make?

  Fertilisers, explosives, and dyes
• What is the Haber process?

  Process that makes ammonia from nitrogen and hydrogen
• What type of reaction occurs in the Haber process?

  A reversible reaction
• What is the chemical equation for the Haber process?

  $N_2(g) +$$3H_2(g) ⇌ 2NH_3(g)$
• What does dynamic equilibrium mean in the context of the Haber process?

  Forward and backward reactions happen at the same rate
• What is the pressure used in the Haber process?

  200 atmospheres
• At what temperature is the Haber process conducted?

  450°C
• What catalyst is used in the Haber process?

  Iron
• Why is iron used in the Haber process?

  It increases the reaction rate without being used up
• Why are unreacted nitrogen and hydrogen recycled in the Haber process?

  It saves money and increases overall yield
• What are the main stages in the Haber process?

  1. Nitrogen extracted from air
  2. Hydrogen obtained from natural gas
  3. Gases pumped through pipes
  4. Pressure increased to 200 atmospheres
  5. Gases heated to 450°C
  6. Passed through iron catalyst
  7. Reaction mixture cooled to liquefy ammonia
  8. Unreacted gases recycled
• What do fertilisers contain that is essential for crops?

  Elements for healthy growth
• How can fertilisers be produced?

  In laboratories and by the chemical industry
• What is a fertiliser?

  A nutrient added to soil
• Why do farmers add fertilisers to the soil?

  To replenish decreasing mineral ion concentration
• What are NPK fertilisers?

  Fertilisers containing nitrogen, phosphorus, and potassium
• What are the three main elements in fertilisers?

  Nitrogen, phosphorus, and potassium
• What must fertiliser compounds be to be absorbed by plants?

  Soluble in water
• What are ammonium ions a source of?

  Soluble nitrogen
• What do phosphate ions provide?

  Soluble phosphorus
• What is the formula for ammonium nitrate?

  NH₄NO₃
• What essential element does urea provide?

  Nitrogen
• What does ammonia produce in neutralisation reactions?

  The ammonium ion (NH₄⁺)
• What can ammonia be oxidised to make?

  Nitric acid (HNO₃)
• What does phosphate rock contain that is useful for fertilisers?

  Phosphorus compounds
• What is produced when phosphate rock reacts with sulfuric acid?

  Single superphosphate
• What is produced when phosphate rock reacts with phosphoric acid?

  Triple superphosphate
• What is the Earth's crust?

  The outer shell of the planet
• Why are potassium chloride and potassium sulfate used as fertilisers?

  They contain potassium ions
• What happens when phosphate rock reacts with nitric acid?

  Produces calcium nitrate and phosphoric acid
• Why can't phosphate rock be used directly as a fertiliser?

  It is insoluble
• What are the main types of fertilisers and their essential elements?

  • Ammonium nitrate: Nitrogen
  • Ammonium sulfate: Nitrogen
  • Ammonium phosphate: Nitrogen, phosphorus
  • Potassium nitrate: Potassium, nitrogen
• What are the processes involved in making fertilisers from phosphate rock?

  1. Phosphate rock reacts with nitric acid:

  • Produces calcium nitrate and phosphoric acid

  1. Phosphate rock reacts with sulfuric acid:

  • Produces single superphosphate

  1. Phosphate rock reacts with phosphoric acid:

  • Produces triple superphosphate
• What is ammonium sulfate's chemical formula?


  (NH4)2SO4
• What is ammonium sulfate primarily used for?

  As a fertilizer
• What is the reaction to produce ammonium sulfate?

  Ammonia reacts with sulfuric acid
• What is the balanced equation for making ammonium sulfate?

  2NH3(aq) + H2SO4(aq) → (NH4)2SO4(aq)
• How is ammonia produced in the chemical industry?

  Through the Haber process