3.4 Equilibria

Question 1

What do reversible reactions attain?

Answer 1

Reversible reactions attain a state of dynamic equilibrium when the rates of forwards and reverse reactions are equal

Question 2

What happens at equilibrium?

Answer 2

Concentration of reactants and products remain constant

Question 3

How does the chemical industry use equilibrium?

Answer 3

The chemical industry employs strategies to move equilibrium in favour of making more products

Question 4

Changing temperature - endothermic

Answer 4

Temperature increase : forwards reaction
Temperature decrease : backwards reaction

Question 5

Changing temperature - exothermic

Answer 5

Temperature increase: backwards reaction
Temperature decrease: forwards reaction

Question 6

Changing pressure

Answer 6

Pressure increase: equilibrium moves to the side with the least gas molecules
Pressure decrease: equilibrium moves to the side with the most gas molecules

Question 7

Catalyst

Answer 7

• No effect on equilibrium
• Increases the rate of the forwards and backwards reaction equally

Question 8

Haber process - pressure

Answer 8

High pressure increases the products at equilibrium

Question 9

Haber process - temperature

Answer 9

Moderate temperatures are used as high temperatures favour the reverse reaction which breaks down ammonia back to the reactants

Question 10

Haber process - catalyst

Answer 10

Use of an iron catalyst increases the rate of ammonia production by achieving equilibrium quicker

Question 11

Haber process - recycling of unreacted gases

Answer 11

Ammonia is easily separated from unreacted nitrogen and hydrogen as ammonia has a much higher boiling point. Unreacted nitrogen and hydrogen are returned to the reaction vessel

Question 12

Haber process - removal of produc

Answer 12

Removal of ammonia product before equilibrium is achieved means the system tries to replace ammonia to try to achieve equilibrium