8. Equilibrium constants and their significance

Question 1

equilibrium constant K with value of 1 indicates

Answer 1

position of equilibrium is halfway between reactants and products

Question 2

equilibrium constant K greater than 1

K<1

Answer 2

reaction is product favoured

products on right hand side predominate at equilibrium

Question 3

equilibrium constant K less than 1

K>1

Answer 3

reaction is reactants favoured

reactants on left hand side predominate at equilibrium

Question 4

how does increase in temperature affect equilibrium

Answer 4

shifts position of equilibrium in endothermic direction △H+ve

Question 5

how does decrease in temperature affect equilibrium

Answer 5

shifts position of equilibrium in exothermic direction △H-ve

Question 6

the only change that affects equilibrium constants Kc and Kp

Answer 6

changes in temperature
(any other changes K remains constant)
k increases as temperature rises if forward reaction is endothermic +ve
k decrease as temperature rises if forward reaction is exothermic -ved

Question 7

the way that K is affected by temperature is linked to

Answer 7

△H

Question 8

if the forward reaction is endothermic △H+ve temperature increase K increases
.
if forward reaction is exothermic △H-ve
temperature increases K decreases

Answer 8

equilibrium yield of products on right increases
equilibrium yield of reactants on left decrease
k=products/reactants
k=2/1= 2 (BIGGER) vs 1/2=0.5
.
equilibrium yield of products on right decreases
equilibrium yield of reactants on left increases
k=products/ reactants
k= 1/2=0.6 SMALLER 2/1=2

Question 9

the value of K is unaffected by changes in

Answer 9

concentration and pressure

Question 10

how dos presence of catalyst affect K

Answer 10

it doesn’t.
catalysts affect rate of a chemical reaction not position of equilibrium.
catalysts speed up forward and reverse reactions by same factor.
equilibrium is reached more quickly.
but equilibrium position and hence value of k is unchanged.