The Haber process

Question 1

reversible reactions

Answer 1

chemical reactions which can be changed in direction by changing the reactant conditions

e.g. ammonium chloride decomposes when heated, but ammonia and hydrogen chloride combine when cool

Question 2

reversible symbol

Answer 2

⇌

used to show that a reaction is reversible/happening in both directions

Question 3

closed system

Answer 3

a container where no reacting substances can enter or leave

Question 4

dynamic equilibrium

Answer 4

in a closed system, a reversible reaction can reach equilibrium:

• rate of forward reaction = rate of backward reaction
• concentration of the reacting substances remain constant

-in a chemical (dynamic) equilibrium, the forward and backward reactions keep going

Question 5

the Haber process

Answer 5

a reversible reaction between nitrogen and hydrogen to form ammonia

Question 6

Describe the setup which ammonia is produced in

Answer 6

nitrogen from air and hydrogen pass through a compressor and enter into a reactor vessel

the reactor vessel has a pressure of 200 atmospheres, and a temperature of 450 C

it also contains an iron catalyst

gas then exits and is cooled

the liquid ammonia is continuously removes, while the nitrogen and hydrogen are recycled back into the reactor vessel so they aren’t wasted

Question 7

Haber process equation

Answer 7

N2 + 3H9g) ⇌ 2NH3

Question 8

The Haber process requires nitrogen and hydrogen. State the raw materials needed to obtain these two reactants. [2]

Answer 8

nitrogen is extracted from the air and hydrogen is obtained from natural gas

Question 9

Hydrated copper sulfate crystals turn from blue to white when they are heated:

hydrated copper sulfate (blue) ⇌ anhydrous copper sulfate (white) + water

a) State why the word equation contains the symbol ⇌ [1]
b) Describe how anhydrous copper sulfate could be used to test for water [2]

Answer 9

a) the symbol means that the reaction is reversible
b) add the substances to be tested to anhydrous copper sulfate, if water is present, it will react with the copper sulfate, causing it to turn blue

Question 10

What is the difference between equilibrium and dynamic equilibrium?

Answer 10

in dynamic equilibrium both reactions are ongoing once they reach equilibrium

a chemical equilibrium is also dynamic

Question 11

Why might equilibrium not be achieved in an open system?

Answer 11

product/reactant can leave, meaning the concentrations are constantly changing, leaving it unable to reach equilibrium