The production of ammonia

Question 1

What is a reversible reaction?

Answer 1

A reversible reaction is one where the products is one where the products of the reaction can themselves react to produce the original reaction.

The reaction can go both ways.

Question 2

What is the state of equilibrium?

Answer 2

Equilibrium means that the amounts of reactants and products will reach a certain balance and stay there.
The reactions are taking place at exactly the same rate in both directions.

Question 3

What is an exothermic reaction and give examples?

Answer 3

These are reactions that transfer energy to the surroundings

Combustion and the neutralisation of acids and alkalis

Question 4

What’s an endothermic reaction and give examples

Answer 4

These are reactions that take in energy from the surroundings

Electrolysis
Thermal decomposition

Question 5

What happens when you raise the temperature in a reversible reaction?

Answer 5

If you raise the temperature, the endothermic reaction will increase to use up the extra heat

Question 6

What happens in a reversible reaction when you reduce the temperature?

Answer 6

If you reduce the temperature, the exothermic reaction will increase to give out more heat

Question 7

Many reactions have a greater volume on one side, either the products or the reactants, what does this mean?

Answer 7

Greater volume means there are more gas molecules and less volume means there are freer gas molecules

Question 8

What happens when you raise the pressure of a reversible reaction?

Answer 8

If you raise the pressure it will encourage the reaction which produces less volume

Question 9

What happens when you lower the pressure of a reversible reaction?

Answer 9

If you lower the pressure it will encourage the reaction which produces more volume

Question 10

What does adding a catalyst do to a reversible reaction?

Answer 10

It doesn’t change the equilibrium position,
Catalysts speed up both the forward and backward reactions by the same amount.
It reached equilibrium quicker but you end up with the same amount of product as you would without the catalyst

Question 11

What two gases are needed to make ammonia?

Answer 11

Nitrogen and hydrogen

Question 12

Where do you get the nitrogen and hydrogen from?

Answer 12

Nitrogen is obtained easily from the air,

Hydrogen comes from natural gas or other sources like crude oil

Question 13

What is the equation for making ammonia?

Answer 13

N_2 + 3H_2 <> 2NH_3

Question 14

What are the industrial conditions for the haber process?

Answer 14

Pressure: 200 atmospheres

Temperature: 450 degrees Celsius

Catalyst: iron

Question 15

What happens when hydrogen and nitrogen react?

Answer 15

Some if the nitrogen and hydrogen react to form ammonia, but because the reaction is reversible, ammonia breaks down again into nitrogen and hydrogen,
The reaction reaches equilibrium

Question 16

Why are higher pressures used in the production of ammonia?

Answer 16

Higher pressures favour the foward reaction so the pressure is

Question 17

What happens when you increase the temperature in the haber process?

Answer 17

The forward reaction is exothermic which means increasing the temperature will move the equilibrium in the wrong way, so the yield of ammonia is greater at lower temperatures

Question 18

What is ammonia formed like?

Answer 18

The ammonia is formed as a gas but as it cools in the condenser it liquifies and is removed

Question 19

What happens to the waste hydrogen and nitrogen

Answer 19

It’s recycled

Question 20

What does the iron catalyst do to the haber process?

Answer 20

The iron catalyst makes the reaction go faster which gets it to the equilibrium proportions more quickly.