6.6- THE EFFECT OF CHANGING CONDITIONS ON EQUILIBRIA

Question 1

What is the effect on Kc, effect on products, effect on reactants + direction of change on equilibrium when temperature is decreased for an endothermic reaction?

Answer 1

effect on Kc- decrease
effect on products- decrease
effect on reactants- increase
direction of change of equilibrium- moves left

Question 2

What is the effect on Kc, effect on products, effect on reactants + direction of change on equilibrium when temperature is increased for an endothermic reaction?

Answer 2

effect on Kc- increase
effect on products- increase
effect on reactants- decrease
direction of change of equilibrium- moves right

Question 3

What is the effect on Kc, effect on products, effect on reactants + direction of change on equilibrium when temperature is increased for an exothermic reaction?

Answer 3

effect on Kc- decrease
effect on products- decrease
effect on reactants- increase
direction of change of equilibrium- moves left

Question 4

What is the effect on Kc, effect on products, effect on reactants + direction of change on equilibrium when temperature is decreased for an exothermic reaction?

Answer 4

effect on Kc- increase
effect on products- increase
effect on reactants- decrease
direction of change of equilibrium- moves right

Question 5

What happens to equilibrium if equilibrium constant Kc increases in value?

Answer 5

equilibrium moves to right, that is, forward direction (more products)

Question 6

What happens to equilibrium constant Kc decreases in value?

Answer 6

equilibrium moves to left, that is, backward direction (less products)

Question 7

What is the general rule for equilibrium constant for an exothermic reaction when increasing temperature?

Answer 7

decreases equilibrium constant

Question 8

What is the general rule for equilibrium constant for an endothermic reaction when increasing temperature?

Answer 8

increases equilibrium constant

Question 9

How will equilibrium change for an exothermic reaction, when the temperature is increased?

Answer 9

will move equilibrium to left

Question 10

How will equilibrium change for an endothermic reaction, when the temperature is increased?

Answer 10

will move equilibrium to right

Question 11

When does the equilibrium constant not change?

Answer 11

if temp not changed

Question 12

What can the size of the equilibrium constant Kc tell us about?

Answer 12

composition of equilibrium mixture

Question 13

If the Kc is much greater than 1 what does this mean?

Answer 13

products predominate over reactants + equilibrium position is over to right

Question 14

If the Kc is much less than 1 what does this mean?

Answer 14

reactants predominate + equilibrium position is over to left

Question 15

What are reactions where equilibrium constant greater than 10^10 usually regarded as?

Answer 15

usually regarded as going to completion

Question 16

What are reactions where equilibrium constant of less than 10^-10 regarded as?

Answer 16

not taking place at all

Question 17

What effect do catalysts have on value of Kc?

Answer 17

no effect on value of Kc

Question 18

Why do catalysts not have an effect on the value of Kc?

Answer 18

as they affect rates of both forward + back reactions equally

Question 19

How do catalysts affect the rate of both forward + backward reactions equally?

Answer 19

reducing activation energy for reactions

Question 20

What DO catalysts affecr?

Answer 20

rate at which equilibrium attained- important in industrial processes

Question 21

In what phase can reversible reactions take place in?

Answer 21

gas phase + in solution

Question 22

How are the gaseous equilibria concentrations expressed differently?

Answer 22

using partial pressure rather than concentrations