1. Equilibrium Rate of Forward Reaction = Rate of Reverse Reaction
Dynamic Equilibrium
Rate of Forward Reaction = Rate of Reverse Reaction
concentration of reactants and products are constant**** they are not equal in amount
Phase
Solution
Chemical
some chemical reactions can reach equilibrium.
• phase changes are reversible
• equilibrium occurs in a
SATURATED SOLUTION
• equilibrium occurs in a closed system
* the rate of the dissolving equals the rate of the undissolved (settling out)
equilibrium is recognized when observable changes such as color, temperature, and pressure no longer change

2. only affects a gas Temperature Concentration LeChatelier’s principle
Increase concentration --(add to the side the compounds on) so –
- equilibrium shifts to the opposite side
Decrease concentration --( removed from the side the compound is on) so –equilibrium shifts to the same side - replacing what you lost
Temperature
Increasing Temp - is like adding energy –shift to opposite side of energy term
Decreasing temp - is like removing energy
-- shifts to same side of energy term
LeChatelier’s principle
When a reaction at equilibrium is stressed it will shift to relieve the stress.
N2(g) H2(g) 2NH3(g) + energy
Shifts to the side from which something is removed
Shifts away from the side something is added to.
Pressure
only affects a gas
Pressure -- shifts to the side with the least number of moles
Pressure - increase volume - shifts to the side with the most moles
mole = the sum of the coefficients
on one side
Catalyst
does not shift
only reaches equilibrium faster

3. Li2SO4(s) = 2Li(aq) + + SO42-(aq)
Common Ion Effect
Add ion to decrease the solubility of a salt
Li2SO4(s) = 2Li(aq) + + SO42-(aq)
What would happen if I add H2SO4
H2SO4 = 2H+ + SO42-
Added SO42- so increasing concentration on the right of ion
Shift the equation to left
Causes Li2SO4 to precipitate (become less soluble)