Equilibrium Flashcards
Catalysts make reactions go faster toward their _______ , but can not change the ____ or change the value of Keq.
equilibrium, equilibrium
Reversible reactions usually do not proceed to _____ because the products can _____ to reform the ______
completion, react, reactants
Dynamic Equilibrium
forward and reverse reactions both occur but at the same rate; thus no net change in the concentration of products and reactants
Static Equilibrium
All reactions are stopped
Entropy
distribution of energy throughout a system or between a system and its enviornment
For a reversible reaction at a given temperature, the reaction will reach equillibrium when the systems ENTROPY is ____ and GIBBS FREE ENERGY is _____
maximum, minimum
Law of Mass Action(Keq)
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 )
Relation between equilibrium constant and rate
ex: 2A < -> B + C
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
At equilibrium, while the forward and reverse REACTION RATES are equal, the concentrations of the reactants and products are…..
not usually equal. THink about the rate constants k
Keq = kf/kr
When a reaction occurs in more than one step, the equilibrium constant for the overall reaction is found by….
multiplying the equilibrium constants for each step
eq: Keq = k1k2k3 / k-1k-2k-3 = ( [C]^c * [D]^d ) / ( [A]^a * [B]^b )
Reaction Quotient (Q)
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 )
Q< Keq
forward reaction has not reached equilibrium
more reactant than products compared at equilibrium
forward reaction rate is increased
Q = Keq
dynamic equilibrium
reactants and products are present at EQUILIBRIUM proportions
forward and reverse reaction rates are equal
Q > Keq
forward reaction has exceeded equilibrium
greater amounts of product than reactants compared at equilibirum
reverse reaction rate is increased to restore equilibrium
Properties of Law of Mass Action
- 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
Le Chateliers Principle
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
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.
gaseous
decreases; increases; partial pressure
lower
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.
volume ; decreases
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 ____.
Keq , equilibrium constant
keq
enthalpy
reactant
product
Kinetic Product
formed with small heat transfer
formed faster
higher gibbs free energy/ less stability
Thermodynamic Product
formed with larger heat transfer
formed slower
lower gibbs free energy/more stability
