19.3 Controlling the position of the equilibrium

Question 1

increasing temperature in an endothermic reaction

Answer 1

increases Kc

Question 2

increasing temperature in an exothermic reaction

Answer 2

decreases Kc

Question 3

why does increasing the temperature in an endothermic reaction increase the Kc?

Answer 3

increasing temperature in an endothermic reaction causes the EQ to shift to the right

the concentration of the products gets larger
and
the concentration of the reactants gets smaller

means a larger value for Kc

Question 4

why does increasing the temperature in an exothermic reaction decrease the Kc?

Answer 4

increasing temp in an exothermic reaction causes the EQ to shift to the left

the concentration of the products gets smaller
and
the concentration of the reactants gets bigger

means a smaller value for Kc

Question 5

is Kc affected by pressure and concentration?

Answer 5

no
it remains constant

Question 6

what does changing the pressure or concentration affect?

Answer 6

the ratio of products to reactants

the EQ then changes to return the ratio back to the Kc value

Question 7

what happens when the concentration of the reactants increases?

Answer 7

you get a smaller value for the ratio of products to reactants

this ratio is smaller than the Kc value so no longer in equilibrium

Question 8

how does the EQ return the ratio to Kc value?

Answer 8

concentration of products increases

concentration of reactants decreases

thus shifting the EQ to the right

causes the ratio to increase back to the Kc value
back to equilibirum

Question 9

do catalysts affect the Kc?

Answer 9

no

Question 10

features of catalyst

Answer 10

increase the rate of a reaction
BUT not the EQ

catalysts speed up both the forward and reverse reactions in an EQ by the same factor