Chapter 19 Ammonia

Question 1

What is a reversible reaction

Answer 1

A reaction that can go both forward and backward at the same time.

Question 2

What is the Haber process?

Answer 2

The process used to manufacture ammonia industrially

Question 3

What are the raw materials for the Haber process

Answer 3

Nitrogen and hydrogen

Question 4

What processes are used to obtain the two raw materials of nitrogen and hydrogen

Answer 4

Nitrogen: fractional distillation of liquid air

Hydrogen: cracking of petroleum

Question 5

State the equation for the Haber process

Answer 5

nitrogen + hydrogen ⇌ ammonia

N2 + 3 H2 ⇌ 2 NH3

Question 6

What conditions are required for the Haber process?

Answer 6

1. 250 atm high pressure
2. 450℃ high temperature
3. Iron used as catalyst

Question 7

Why is 450℃ considered the optimum temperature for the Haber process?

Answer 7

450℃ is optimal temperature as it is low enough that not much ammonia decomposes, but does not result in a slow reaction

Question 8

Explain the Haber process in full including the components used

Answer 8

1. Nitrogen and hydrogen are mixed in 1:3 proportion by volume
2. Gases are compressed to 250 atm inside a compressor
3. Gases are heated to 450℃ and passed over finely divided iron catalyst inside a converter containing beds of finely divided catalyst

Only 10 to 15% of nitrogen & hydrogen are converted to ammonia

4. Mixture of ammonia, nitrogen and hydrogen passes into the cooling chamber and is cooled.
5. Ammonia condenses to form liquid ammonia.
6. Remaining gases are recycled and used in the process again

Question 9

What happens when an ammonium salt is heated with an alkali?

Answer 9

Ammonia is displaced from the salt.