Equilibrium Flashcards
Define Equilibrium
- closed system
- forward rxn equal rate to backwards rxn
Achieved Equilibrium
concentration remain constant, all measurable properties are constant (temp. press, color)
Le Chatelier’s principle
- When system is exposed to change, equilibrium shifts to counteract the stress
- New equilibrium is made after a stress
- changes can be temp, pressure (only for gases) or concentration
Effects of catalysts in equilibrium
Reactions are able to reach equilibrium faster but there is no shift
Effect of inert gases in equilibrium
noble gases: Mix w/ original gases, dont change volume, no shift
Graphs: changes indication
Concentration: one peak
Temperature: no peak
Pressure: all peak
what effects the equilibrium constant (Kc)
different temp = new Kc
Kc > 1
products r favored (right shift)
Kc < 1
favors reactants (left shift)
Kc = 0
no sides are favoured
Homogenous Equilibrium
All species are in same state
Heterogeneous equilibrium
mixed states
- liquids and solids are not relevant in calculation of Kc
pOH and pH are logarithmic scales, they increase by
1=10
ex. pH 2 to 4 = 100
Original Arrhenius Theory
- Bases produce OH-
- Acids produce H
- Use for strong bases
Modified Arrhenius Theory
- Bases reacts w/ H2O to produce OH-
- Acids react w/ H2O to produce H3O+
- Use on SA, WA, and WB
Define acids
- sour
- red litmus
- pH < 7
- pOH > 7
- donate H
Define Base
- bitter
- blue litmus
- pH > 7
- pOH < 7
- accepts H
Bronsted-Lowry Theory
- forward and reverse rxn involve transfer of proton (H)
- Acid and base on both sides of rxn
Amphiprotic
acts as base or acid
- has H & neg charge
Rule of 1000
- [acid] / ka
- [base] / kb
- more than 1000 makes C insignificant so I and E are same
Ranking
Side with weaker acid is favoured
Buffers
- Made of weak acid or base w/ its conjugate
- Purpose is to maintain constant pH
Buffer characteristics
- pH of solution determines where buffers would be appropriate
- buffer capacity: how effective buffer is in system
- buffer region on graph: pH is constant
How to find Ka or Kb
- ice table
- Kw = Ka x Kb
