3.1.6 Equilibria

Question 1

Rate of forward reaction =?

Answer 1

• Rate of backward reaction and concentration of products and reactants remain constant, therefore chemical equilibria has been achieved.

Question 2

Define Le Chatelier’s prinicple.

Answer 2

• If there’s a change in concentration, pressure or temperature, the equilibrium will move to help counteract the change.

Question 3

What is the effect of increasing the pressure?

Answer 3

• Equilibrium will shift to the side that contains fewer gaseous moles, therefore yield of product increases.

Question 4

What is the effect of increasing temperature when the reaction is exothermic?

Answer 4

• Favours the backward reaction, so the equilibrium shifts to the left, therefore the yield of product decreases.

Question 5

What is the effect of decreasing temperature when the reaction is endothermic?

Answer 5

• This favours the backward exothermic reaction so the equilibrium shifts to the left, therefore yield of product decreases.

Question 6

Why does adding a catalyst make no difference on the position of the equilibrium?

Answer 6

• A catalyst speeds up the forward and backward reaction equally.

Question 7

How do you work out Kc?

Answer 7

• Products/reactants.

Question 8

What does it mean when the Kc value is large speaking in terms of the position of the equilibrium?

Answer 8

• The equilibrium shifts to the right.