Equilibrium

Question 1

Catalysts make reactions go faster toward their _______ , but can not change the ____ or change the value of Keq.

Answer 1

equilibrium, equilibrium

Question 2

Reversible reactions usually do not proceed to _____ because the products can _____ to reform the ______

Answer 2

completion, react, reactants

Question 3

Dynamic Equilibrium

Answer 3

forward and reverse reactions both occur but at the same rate; thus no net change in the concentration of products and reactants

Question 4

Static Equilibrium

Answer 4

All reactions are stopped

Question 5

Entropy

Answer 5

distribution of energy throughout a system or between a system and its enviornment

Question 6

For a reversible reaction at a given temperature, the reaction will reach equillibrium when the systems ENTROPY is ____ and GIBBS FREE ENERGY is _____

Answer 6

maximum, minimum

Question 7

Law of Mass Action(Keq)

Answer 7

if the system is at equilibrium at a constant temperature, then the following ratio is constant

Keq = ( [C]^c * [D]^d ) / ( [A]^a * [B]^b )

Question 8

Relation between equilibrium constant and rate

ex: 2A < -> B + C

Answer 8

rate f =kf[A]^2
rate r = kr[B][C]

Keq = [B][C] / [A]^2

at equilibrium rate f = rate r

kf[A]^2 = kr[B][C]

kf / kr = [B][C] / [A]^2 = Keq

Question 9

At equilibrium, while the forward and reverse REACTION RATES are equal, the concentrations of the reactants and products are…..

Answer 9

not usually equal. THink about the rate constants k

Keq = kf/kr

Question 10

When a reaction occurs in more than one step, the equilibrium constant for the overall reaction is found by….

Answer 10

multiplying the equilibrium constants for each step

eq: Keq = k1k2k3 / k-1k-2k-3 = ( [C]^c * [D]^d ) / ( [A]^a * [B]^b )

Question 11

Reaction Quotient (Q)

Answer 11

used as a tracker to measure concentrations of all reactants/products CURRENTLY in the reaction, NOT at equilibirum

Q = ( [C]^c * [D]^d ) / ( [A]^a * [B]^b )

Question 12

Q< Keq

Answer 12

forward reaction has not reached equilibrium

more reactant than products compared at equilibrium

forward reaction rate is increased

Question 13

Q = Keq

Answer 13

dynamic equilibrium

reactants and products are present at EQUILIBRIUM proportions

forward and reverse reaction rates are equal

Question 14

Q > Keq

Answer 14

forward reaction has exceeded equilibrium

greater amounts of product than reactants compared at equilibirum

reverse reaction rate is increased to restore equilibrium

Question 15

Properties of Law of Mass Action

Answer 15

• concentration of solids and liquids do not appear in expression, they are equal to 1
• Keq is dependent at temperature
• The larger the Keq, the father to the right the equilibrium position
• If in one direction equilibrium constant is Keq, the reverse direction is 1/Keq

Question 16

Le Chateliers Principle

Answer 16

if a stress is applied to a system, the system shifts to relieve that applied stress as the stress shifts it from equilibrium

examples are addition/subtraction of reactant/product

Question 17

Only chemical reactions that involve at lease one ______ species will be affected by changes in the systems pressure and volume.

When a system is compressed, volume ____ and pressure _____ , leading to increase in ______ of gasses within the state and the system no longer being in equilibrium state.

System will move forward or in reverse towards whichever side has the ____ total number of moles of gas.

Answer 17

gaseous

decreases; increases; partial pressure

lower

Question 18

When one expands _____ of a system, total pressure and partial pressures ____ and the system will react in the direction of the side with the greater number of moles of gas to restore/increase pressure.

Answer 18

volume ; decreases

Question 19

Change in temperature will not change reaction quotient, but change the ____ . Immediately after the temp change, Q is unaffected but ___ is thus Q does not equal Keq, so system moves in whichever direction reaches the new equilibrium state.

Direction is dependent on _____ of the reaction. If reaction is EXOthermic, heat functions as a _____. If reaction is ENDOthermic, heat functions as a ____.

Answer 19

Keq , equilibrium constant

keq

enthalpy

reactant

product

Question 20

Kinetic Product

Answer 20

formed with small heat transfer

formed faster

higher gibbs free energy/ less stability

Question 21

Thermodynamic Product

Answer 21

formed with larger heat transfer

formed slower

lower gibbs free energy/more stability