Ch. 6: Equilibrium Flashcards
dynamic equilibrium
forward and reverse reactions occur at the same rate with no net change in the concentrations of the products
static equilibrium
forward and reverse reactions have stopped
when do reversible reactions reach equilibrium
- entropy (energy dispersion) is at maximum
- Gibbs free energy is at minimum
ratio of Kf to Kr to Kc
Kc = Keq = Kf/Kr
equation for reaction quotient, Q
Q = [C]^c [D]^d / [A]^a [B]^b
for a point in time of the reaction
when does the reaction proceed in the forward direction (in terms of Q, Keq, and delta G)
when Q < Keq and delta G < 0
when does the reaction in dynamic equilibrium (in terms of Q, Keq, and delta G)
Q = Keq and delta G = 0
when does the reaction proceed in the reverse direction (in terms of Q, Keq, and delta G)
when Q > Keq and delta G > 0
Le Chatelier’s Principle
if stress is applied to a system, the system shifts to relieve that stress
How does a system shift if reactants are added or products are removed
Qc < Keq
reaction spontaneously moves forward until Qc = Keq
How does a system shift if reactants are removed or products are added
Qc > Keq
reaction spontaneously moves in reverse until Qc = Keq
how do changes in pressure/volume affect a system
only applies to gas reaction
changes in volume –> pressure
high pressure favors side of a rxn with less moles
low pressure favors side of a rxn with more moles
how do changes in temperature affect a system
exothermic = heat is a product endothermic = heat is a reactant
equilibrium will shift to balance change in temp
kinetic product
- lower temperature
- faster (less energy to react)
- less stable product
thermodynamic product
- higher temperature
- slower (more energy to react)
- more stable product
