Equilibrium 3.10.4

Question 1

Dynamic Equilbrium

Answer 1

The rate of the forwards reaction equals the rate of the backwards reaction in a closed system.

Question 2

Le Chatelier’s principle

Answer 2

If the conditions are changed, the position of the equilibrium will shift to minimise the change.

Question 3

Which equilibrium does this principle occur?

Answer 3

This only works in homogenous equilibria (reactants and products in the same states)

Question 4

What happens if you increase the concentration of reactants?

Answer 4

Equilibrium will shift to the right to use it up and reduce the concentration and so more products will be formed.

Question 5

What will happen if you increase the pressure equilibrium?

Answer 5

Equilibrium will shift to the side with the fewest number of gaseous moles this will reduce the pressure. (If U decrease it was shift to the side with the most number of gaseous moles)

Question 6

What energy change is the forwards reaction?

Answer 6

Exothermic -^H

Question 7

What is energy change is backwards reaction?

Answer 7

Endothermic +^H

Question 8

What will happen if you increase the temperature equilibrium?

Answer 8

The temperature equilibrium will shift in the endothermic direction this will reduce the temperature.

Question 9

What is the effect of a catalyst on the position of equilibrium?

Answer 9

Catalyst have no effect on the position of equilibrium. This is because it will speed up the rate of forwards and backwards reaction equally. It will effect the rate but no effect on yield.

Question 10

What are the downsides of using pressure?

Answer 10

High pressure environments are expensive due to thicker more robust vessels and pipes needed. There is compromise between yield and cost.

Question 11

What equation is used for the equilibrium constant?

Answer 11

aA (aq) + bB (aq) = cC (aq) + dD (aq)

Kc = [C]c x [D]d
—————
[A]a x [B]b

Question 12

What units are used for the Kc

Answer 12

mol-1dm3

Question 13

What is the effect on temperature on the value of Kc?

Answer 13

If temperature change causes equilibrium to shift right Kc will increase.

Question 14

What will happen to the position of the equilibrium if you increase the temperature?

Answer 14

The equilibrium would shift to minimise the effect of temperature rise by absorbing energy. (Foward reaction is exo) (backwards is endo)