Equilibrium

Question 1

what does irreversible mean

Answer 1

when the reaction proceeds in one direction only, goes to completion, and the maximum amount of product formed is determined by the amount of limiting reagent initially present

Question 2

what does reversible mean

Answer 2

when the reaction can proceed in either direction, usually doesn’t not go to completion and usually goes into dynamic equilibrium (when the system’s entropy is at a maximum and gibbs free energy is at a minimum)

Question 3

what is the law of mass action

Answer 3

states that if the system is at equilibrium at a constant temperature, then the following ration is constant
Keq= [C]^c[D]^d/[A]^a[B]^b

Question 4

what is the reaction quotient, Q

Answer 4

essentially serves as a timer to indicate how far the reaction has proceeded toward equilibrium
Qc = [C]^c[D]^d/[A]^a[B]^b

Question 5

what does it mean when Q < Keq

Answer 5

the forward reaction has not yet reached equilibrium
there is a greater concentration of reactants
the forward rate of reaction is increased to restore equilibrium

Question 6

what does it mean when Q = Keq

Answer 6

the reaction is in dynamic equilibrium
the reactants and products are present in equilibrium proportions
the forward and reverse rates of reaction are equal

Question 7

what does in mean when Q > Keq

Answer 7

the forward reaction has exceeded equilibrium
there is a higher concentration of products
the reverse rate of reaction is increased to restore equilibrium

Question 8

Keq is a characteristic of particular reaction at a given temperature; therefore the equilibrium constant is

Answer 8

temperature-dependent

Question 9

the larger the value of Keq …

Answer 9

the farther to the right the equilibrium position

Question 10

if the concentration of products is greater than the concentration of reactants, Keq must be

Answer 10

greater than 1 or Keq > 1

Question 11

if the concentration of reactants is greater than the concentration of the products, Keq must be

Answer 11

less than 1 of Keq < 1

Question 12

what does a large positive exponent in Keq mean

Answer 12

the reaction strongly favors products at equilibrium
the larger the exponent, the less reactant that will be present at equilibrium
the reaction goes almost to completion

Question 13

what does a large negative exponent in Keq mean

Answer 13

the reaction strongly favors reactants at equilibrium

Question 14

What does Le Chatelier’s Principle state

Answer 14

that if a stress is put on a system, the system shifts to relieve that applied stress

Question 15

if reactants are added/products are removed to a reaction in equilibrium, what direction will the reaction proceed

Answer 15

this means Qc < Keq
this means that the reaction will spontaneously proceed in the forward direction

Question 16

if reactants are removed/products are added to a reaction in equilibrium, what direction will the reaction proceed

Answer 16

this means that Qc > Keq
this means that the reaction will spontaneously proceed in the reverse direction

Question 17

what kind of chemical reactions will be affected by changes and pressure and volume

Answer 17

reactions with at least 1 gaseous species

Question 18

if a system is compressed, what direction will the reaction proceed

Answer 18

if the system is compressed, this means that the pressure has increased
the reactions will move toward the side of the reactions that has fewer moles of gas

Question 19

if a system expands, what direction will the reaction proceed

Answer 19

if the system expands, that means the pressure has decreased
the reaction will move towards the side of the reaction that has more moles of gas

Question 20

what does a change in temperature change: the Keq or the Q

Answer 20

the Keq is changed
the change in temperature does not cause the partial pressures or the concentrations to change immediately

Question 21

if the reaction is endothermic (H>0) heat functions as

Answer 21

a reactant

Question 22

if the reaction is exothermic (H<0) heat functions as

Answer 22

a product

Question 23

if heat is added and the temperature increases, the reactions shifts to the

Answer 23

right

Question 24

if heat is removed and the temperature decreases, the reactions shift to the

Answer 24

left