1. Unit 13: Solutions & Equilibrium
Section 4: Chemical Equilibrium

2. Equilibrium:
two opposing processes occurring at the same rate to achieve balance
Players enter and leave the game, but…
the same total number of players on field.

3. Club Equilibrium (200 max) 200 VIP 180 (20 max) 20 RateIN equal
Con-Con Requal
Club Equilibrium
(200 max)
At Equilibrium:
Concentrations:
VIP
(20 max)
200
180
constant
Rates: 20
equal
200 (Club)
RateIN
180
180
equal 20 20
RateOUT
0 (VIP)

4. Con-Con Requal
H2O(l) ⇄ H2O(g)
Phase Change
Equilibrium

5. Rate of Crystallization
Saturated Solution Equilibrium
Rate of Solvation =
Rate of Crystallization
Con-Con Requal
total moles of dissolved NaCl remains constant
total moles of undissolved NaCl(solid) remains constant

6. Concentrations of prod’s/react’s remain constant, but not equal
Ratef(N2O4)
Rateforward =
Ratereverse
Rater(NO2)
Dynamic
Equilibrium ⇄
N2O4(g)
2 NO2(g)
Concentrations of prod’s/react’s remain constant, but not equal

7. Quick Quiz!
1) When a reaction has reached equilibrium, reactants and products …
A) have stopped reacting.
B) continue forming.
C) have equal concentrations.
D) decrease in concentration. 7

8. A B ⇄
Quick Quiz.
100
2) A reaction starts with 100 molecules of reactant and no product. As it approaches equilibrium, the forward rate will ________ and the reverse rate will ________.
A) remain constant , increase
B) decrease , remain constant
C) increase , decrease
D) decrease , increase 8

9. A B ⇄
Quick Quiz.
100
3) A reaction starts with 100 molecules of reactant and no product. At equilibrium, the amount of product B will be…
A) greater than A
B) less than A
C) equal to A
D) constant 9