Ammonia

Question 1

Uses of ammonia

Answer 1

• Most important use is for making fertilizers

- Also used in making of plastics, explosives, refrigerants

Question 2

How is nitrogen obtained for the Haber process?

Answer 2

• Nitrogen is obtained from the fractional distillation of liquid air.
• Air is cooled and compressed into a liquid and seperated by fractional distillation to obtain nitrogen gas

Question 3

How is hydrogen obtained for the Haber process

Answer 3

• Hydrogen is obtained from the cracking of petroleum. Cracking is breaking down long hydrocarbon chains into smaller molecules
• Example from organic chem
  C8H18 → C5H10 + C3H6 + H2

Question 4

Equation of reaction of nitrogen and hydrogen (Haber process)

Answer 4

N2(g) + 3H2(g) ⇌ 2NH3(g)

Question 5

Conditions for Haber process

Answer 5

• Pressure of 250 atm
• Temperature of 450°C
• Presence of finely divided iron catalyst

Question 6

Displacement of ammonia from its salts

Answer 6

Ammonia salts can react with alkalis with heating to produce ammonia gas

                                heat NH4Cl(s) + NaOH(aq) → NH3(g) + H2O(l) + NaCl(aq)

Question 7

Why are unreacted hydrogen gas and nitrogen gas recycled during the Haber process

Answer 7

This is done in order to save money as the reaction is reversible, and to obtain a higher yield of ammonia gas (recycled unreacted H2 and N2 is used so that do not need to produce more N2 and H2 for the reaction to occur)