Le Chatelier's Principle

Question 1

A system is in dynamic equillibrium if (3 points)

Answer 1

1. It is a closed system
2. The forward reaction is at the same rate as the reverse reaction
3. Concentration of reactants and products remain the same

Question 2

If concentration of reactants > products

Answer 2

Equilibrium shifts to the right to favour the forward reaction in order reduce the concentration of the reactants. This increases the concentration of the products.

Question 3

If concentration of products > reactants

Answer 3

Equilibrium shifts to the left to favour the reverse reaction in order to reduce the concentration of the products. This increases the concentration of the reactants

Question 4

Pressure doesn’t affect equilibrium position if (2 points)

Answer 4

The reactants and products are not gaseous, and they have the same number of moles

Question 5

If pressure increases

Answer 5

The equilibrium will shift to the side with fewer moles in order to decrease the pressure

Question 6

Le Chatelier’s Principle

Answer 6

If a system in dynamic equilibrium is disturbed by a change in temperature, pressure or concentration of one of the components the position of equilibrium will shift in order to oppose the effect of this change so that dynamic equilibrium is maintained.

Question 7

If pressure decreases

Answer 7

The equilibrium will shift to the side with more moles in order to increase the pressure

Question 8

If temperature increases

Answer 8

The equilibrium will shift towards the direction in which the endothermic reaction will be favoured as it will decrease the pressure

Question 9

If temperature decreases

Answer 9

The equilibrium will shift towards the direction in which the exothermic reaction will be favoured as it will increase the pressure

Question 10

Effect of a catalyst

Answer 10

1. No change to the position of equilibrium

2. Equilibrium is reached faster as rate increases

Question 11

What does a catalyst do?

Answer 11

Increase the rate of the forward and the reverse reactions equally

Question 12

What temperature is used in industry?

Answer 12

High temperature

Question 13

Why are low temperatures not used in industry? (2 points)

Answer 13

1. Slow rate of reaction

2. Slow rate means equilibrium may not be established

Question 14

What pressure is used in industry?

Answer 14

Low pressure

Question 15

Why are high pressures not used in industry?

Answer 15

1. Health and safety risk as their is a higher chance of explosion
2. It is more expensive as strong containers are needed and it needs high energy requirements