Equilibrium Flashcards
Equilibrium
A Dynamic State, meaning its not just a reactant or product; your reactant is constantly being converted into products and products are constantly being converted into reactants.
Rate of Forward Reaction = Rate of Reverse Reaction
Chemical Equilibrium of:
N(2)O(4) = 2NO(2)
K(equilibrium) = k(foward) / k(reverse) so…
K(equilibrium) = {NO(2)}^2 / {N(2)O(4)}
Note that:
k(forward) = “Second Thing”
k(reverse) = “First Thing”
- k is lowercase except for the K(equilibrium) *
K Constant Equilibrium
Just tells you the ratio between products^m over reactants^n
where m and n are stoichiometric coefficients
Will be using Molarity hints the brackets
Only applied to aqueous solutions; IGNORE solids, pure liquids, and gasses
NO UNITS
Equilibrium constants DEPEND on temperature
K(eq) VS K(p)
K(eq) = Equilibrium constant for aqueous solutions
K(p) = Equilibrium constant for gasses (p for pressure)
Converting between K(eq) and K(p)
K(p) = K(c)*(RT) ^ delta(n) and K(c) = K(p) * (RT) ^ -delta(n)
where:
R = gas constant = 0.0821
T = Temperature
delta(n) = moles of gas product - moles of gas reactant
K(c) being reactant or product favored
if K(c) greater than 1, it is product favored
if K(c) less than 1, it is reactant favored
Finding Equilibrium constants if A = B gives you K
B = A (flipping A and B) gives you 1 / K
2A = 2B (multiply equation by 2) gives you K ^ 2
if C = D gives you K(1) and E = F gives you K(2) and want to add these together to get C + E = F + D gives you
K(1) * K(2)
Reaction Quotient
Denoted as Q(c)
Is for non equilibrium concentrations
Basically the same as K, but is not at equilibrium:
shows the general flow of from either reactants to products or vise versa
If Q > K:
reaction proceeds to the LEFT
if Q < K:
reaction proceeds to the RIGHT
if Q != K:
Reaction will spontaneously move towards
equilibrium
Le Chatelier’s Principle
Le-Shat-Lee-ay
Predicts what will happen if a system at equilibrium is put under stressed.
Predicts how a change in temperature will affect an equilibrium constant
An equilibrium system when “disturbed” will shift its equilibrium position to counteract the effect
Le Chatelier’s Principle (Shifting Rules)
Le-Shat-Lee-ay
Increasing Reactant = right shift
Decreasing Reactant = left shift
Increasing Product = left shift
Decreasing Product = right shift
Increasing Overall Pressure/ Decreasing Volume =
will shift to the side with the fewest number of molecules
Le Chatelier’s Principle (Temperature Change)
Le-Shat-Lee-ay
Endothermic: Add heat to the reactant side
Temperature increase = right shift = K increases
Temperature decrease = left shift = K decreases
Exothermic: Add head to the product side
Temperature increase = left shift = K decreases
Temperature decrease = right shift = K increases
Equilibrium Constants and Gibbs Free Energy
deltaG = deltaG! + RT * ln(Q)
where,
deltaG! = -RT * ln(K)
K = e ^ (deltaG! / RT)
At equilibrium:
deltaG = 0
Q = K
