Chemical Equilibria (factors affecting POE)

Question 1

how is position of equilibrium affected when concentration of reactant increases amd what happens to the [reactant]

Answer 1

By increasing [reactant]system will counteract the increase bytarouting the forward reaction that uses up reactant, allowing the increased [reactant] to be partially offset as position of equilibrium shifts to the right

New eqm [reactant] is still higher than the initial eqm [reactant] as the change is only partially offset

Question 2

how is position of equilibrium affected when concentration of reactant decreases amd what happens to the [reactant]

Answer 2

By decreasing [reactant] system will counteract the increase by favoring the backward reaction that produces more reactant, allowing the decreased [reactant] to be partially offset as position of equilibrium shifts to the left
New eqm [reactant] is still lower than the initial eqm [reactant] as the change is only partially offset

Question 3

how is position of equilibrium affected when concentration of product increases amd what happens to the [product]

Answer 3

By increasing [product] system will counteract the increase by favoring the backward reaction that uses up more reactant, allowing the increased [product] to be partially offset as position of equilibrium shifts to the left
New eqm [products] is still higher than the initial eqm [product] as the change is only partially offset

Question 4

how is position of equilibrium affected when concentration of product decreases amd what happens to the [product]

Answer 4

By decreasing [product] system will counteract the decrease by favoring the forward reaction that uses up more reactant, allowing the decreased [product] to be partially offset as position of equilibrium shifts to the right
New eqm [products] is still higher than the initial eqm [products] as the change is only partially offset

Question 5

what happens when total pressure of eqm mixture is increased
(Reaction is PCl3 (g) + Cl2 (g) ⇌ PCl5 (g))

Answer 5

By increasing total pressure of eqm mixture, system will counteract the increase in total pressure by favoring the forward reaction that produces fewer gaseous particles, allowing the increase in pressurr to be partially offset as position of equilibrium shifts to the right

Question 6

what happens when total pressure of eqm mixture is decreased
(Reaction is PCl3 (g) + Cl2 (g) ⇌ PCl5 (g))

Answer 6

By decreasing total pressure of eqm mixture, system will counteract the decrease in total pressure by favoring the backward reaction that produces more gaseous particles, allowing the decrease in pressurr to be partially offset as position of equilibrium shifts to the left

Question 7

How will a change in total pressure affect the system with an equal number of gaseous reactants and products

Answer 7

Since the number of gaseous particles on both sides is equal, the change in total pressure does not favor the forward or backward reaction
Position of equilibrium shifts neither to left or right, remaining unaffected amd system remains at equilibrium

Question 8

what happens when volume of eqm mixture is increased umder constant temperature
(Reaction is PCl3 (g) + Cl2 (g) ⇌ PCl5 (g))

Answer 8

By increasing volume under constant T, total pressure of eqm mixture decreases, system will counteract the decrease in total pressure by favoring the backward reaction that produces more gaseous particles, allowing the decrease in pressure to be partially offset as position of equilibrium shifts to the left

Question 9

how is rate of reaction affected when volume of reaction system increased under constant T

Answer 9

When volume increased, partial pressure of all gases decrease and since pressure is directly proportionate to concentration, conc will decrease and rate of both forward and backward rxn decrease
The reaction takes a longer time to reach eqm

Question 10

what happens when volume of eqm mixture is decreased umder constant temperature
(Reaction is PCl3 (g) + Cl2 (g) ⇌ PCl5 (g))

Answer 10

By decreasing volume under constant T, total pressure of eqm mixture increases, system will counteract the increase in total pressure by favoring the forward reaction that produces less gaseous particles, allowing the increase in pressure to be partially offset as position of equilibrium shifts to the right

Question 11

how is rate of reaction affected when volume of reaction system decreased under constant T

Answer 11

When volume decreased, partial pressure of all gases increase and since pressure is directly proportionate to concentration, conc will decrease and rate of both forward and backward rxn increase
The reaction takes a shorter time to reach eqm

Question 12

what happens when an inert gas is added to a gaseous system at constant volume
(Reaction is PCl3 (g) + Cl2 (g) ⇌ PCl5 (g))

Answer 12

Total pressure of a gaseous system increases
Concentrations/partial pressure of products and reactants remain unchanged
Equilibrium position is not affected

Question 13

what happens when an inert gas is added to a gaseous system at constant pressure
(Reaction is PCl3 (g) + Cl2 (g) ⇌ PCl5 (g))

Answer 13

Total volume of the gaseous system is increased as the system must expand to keepits total pressure constant
Concentrations/ partial pressure of the reactants and products are decreased
Equilibrium position will shift to the left where greater number of moles of gas are produced

Question 14

what happens when temp increases for a system at eqm with an endothermic forward reaction

Answer 14

By increasing temp system will counteract the increase by favoring the forward endothermic reaction that absorbs heat, allowing the increased temp to be partially offset as position of equilibrium shifts to the right
New eqm mixture contains more products and less reactants

Question 15

what happens when temp decreases for a system at eqm with an endothermic forward reaction

Answer 15

By decreasing temp system will counteract the decrease by favoring the backward exothermic reaction that released heat, allowing the decreased temp to be partially offset as position of equilibrium shifts to the right

Question 16

Impact on eqm constant when temp increases for a system at eqm with an endothermic forward reaction

Answer 16

New eqm mixture contains more products and less reactants
Eqm constant increases

Question 17

Impact on eqm constant when temp decreases for a system at eqm with an endothermic forward reaction

Answer 17

New eqm mixture contains less products and more reactants
Eqm constant decreases

Question 18

what happens when temp increases for a system at eqm with an exothermic forward reaction

Answer 18

By increasing temp system will counteract the increase by favoring the backward endothermic reaction that absorbs heat, allowing the increased temp to be partially offset as position of equilibrium shifts to the left

Question 19

Impact on eqm constant when temp increases for a system at eqm with an exothermic forward reaction

Answer 19

New eqm mixture contains more reactants and less products
Eqm constant decreases

Question 20

what happens when temp decreases for a system at eqm with an exothermic forward reaction

Answer 20

By decreasing temp system will counteract the decrease by favoring the foward exothermic reaction that releases heat, allowing the decreased temp to be partially offset as position of equilibrium shifts to the right

Question 21

Impact on eqm constant when temp decreases for a system at eqm with an exothermic forward reaction

Answer 21

New eqm mixture contains more products and less reactants
Eqm constant increases

Question 22

Effects of temp increase on time taken to reach eqm

Answer 22

When temp increases, the rate constants k of both the forward and backward reactions increase, since the number of particles with energy greater than or equal to the activation energy increases
Rate of forward amd backward reactions both increase and dynamic eqm is reached faster
Time taken decreases

Question 23

Effect of temp decrease on time taken to reach eqm

Answer 23

When temp decreases, the rate constants k of both the forward and backward reactions decrease, since the number of particles with energy greater than or equal to the activation energy decrease
Rate of forward amd backward reactions both increase and dynamic eqm is reached slower
Time taken increases

Question 24

Effect of catalyst on eqm constant, POE and time taken to reach eqm

Answer 24

Catalyst lowers activation energy of both the forwardand backward reactions to the same extent so rates of both the forward and backward reactions are increased to the same extent so eqm will be reached faster but POE is remains the same
Catalyst will have no effect on eqm constant and the composition of eqm mixture

Question 25

Why is temperature of 450 used in industrial production ofammorta

Answer 25

Forwardreaction of ammonia is exothermic so lower temp will result in a higher yield but at low temp rate of production is too low
High temp increases rate of production but results in lower yield and higher production cost
Compromise of moderately high temperature of 450 is used to ensure reasonable rate of production and yield

Question 26

Why is a pressure of 200 atm used in industrial production of ammonia

Answer 26

A high pressure will favor the desired forward reaction that produces less gas particles
However high pressure increases cost of production and increases safety concerns
Moderate pressure of 200 atm is used

Question 27

What catalyst is used and why is it used in industrial production of ammouth

Answer 27

Finely divided iron catalyst with aluminum oxide as promoter
To increase production rate

Question 28

Why is ammonia reaction mixture continuously cooled during production

Answer 28

To liquefy ammonia formed so that ammonia is continuously removed
Removal of ammonia shifts position of equilibrium to the right and increases yield of ammonia

Question 29

Why are nitrogen and hydrogen used in the ratio of 1:3 in ammonia production

Answer 29

Molar ratio used is similar to that of the stoichiometric ratio to minimise excess