Unit 4: Equilibrium
Theory
Application
Le Chatelier's Principle - An equilibrium equation will always try to counteract an external stress done on it
Equilibrium Constant (K)
Equilibrium - When the forward reaction and the reverse reaction equal each other in rate. System Must be closed with constant pressure and temperature
Lower Enthalpy and Higher Entropy is always Favoured in equilibrium
Gibbs Free Energy (ΔG = ΔH – TΔS)
Examples of stress: Addition of a product/reactant.
Volume Changes
Pressure Changes
Temperature Changes
The Haber Process (N2 (g) + 3H2 (g) ⇌ 2NH3 (g) ) Was a great development as it was one of the first fertilizers that's used
Equilibrium Law Expression( K= (A)(B)/(C)(D) )
The Expression can only include concentration of Gases and Aqueous solutions
Equilibrium Quotient ( Q= (A)(B)/(C)(D) ) shows the expression when the reaction may not be in equilibrium.
If Q = K, the system is at equilibrium.
If Q > K, the system will adjust left (to reactants) to achieve equilibrium.
If Q < K the system will adjust right (towards products) to achieve equilibrium.
RICE Tables - a type of problem solver very useful in equilibrium problems, helps determine concentrations
Solubility
Solids Dissolving in Liquids
Gases Dissolving in Liquids
Also has a constant known as the Solubility Product Ksp= (A)(B)/(C)(D)
Solubility increases with increasing temps
Solubility decreases with increasing temps
Acid and Base Titrations
Lewis definition - Electron Pair Acceptor(Acid)/ Giver(Base)
Bronsted Lowry Definition - Proton Accepter(Base)/ Giver(Acid).
Qualitative Observations of Acids: Sour Taste, Soluble in water, Turns Litmus Red
Qualitative Observations of Bases: Bitter Taste, Soluble in water (Can be insoluble), Turns Litmus Blue
pH is a number on a scale that represents the concentration of [H3O+] Ions. pH = -log([H3O+]. 7 is neutral, below 7 is acidic, above 7 is basic
pOH is a number on a scale that represents the concentration of [OH-] Ions. pH = -log([OH-]. 7 is neutral, below 7 is Basic, above 7 is Acidic
pH indicators can be used to tell the acidity of a solution. Certain ones are better some applications than others. Preferably you should use the ones that go from no color to color
Equilibrium with Acid and Base Titrations have either Ka(for Acid) or Kb(for Base)
(Kb)(Ka) = Kw = 1.0 10^-14
100 rule, if the initial concentration is 100x the Ka or Kb value, you can simplify the equation
This is a RICE table for solublity
This is a RICE table for Titration
Connection to Unit 1: Properties of solids. In equilibrium we learned about the Haber process. We also learned that in the process lowering the temperature in the system allows us to yield more ammonia, this is because ammonia has Non-Polar bonds versus the Atomic Molecules Nitrogen and Hydrogen, this means it turns to liquid at a higher temperature which means you can yield more NH3 and allow the reaction to occur faster in the products direction
Connection to Unit 2: Thermo and Rates. If you apply energy to an Exothermic reaction the reaction would shift to the reactants, if you apply energy to an Endothermic reaction the reaction would shift to the products. This then shows that the Haber Process is an Exothermic reaction because taking energy away (Lowering temperature) Favors the products side.
Connection to Unit 5: Bases can conduct electricity in water if they are soluble Means they are electrolytes
Connection to Unit 5: Acid can conduct electricity in water. Means they are electrolytes
Connection to Unit 2: Thermo and Rates. In a concentration time graph of a reaction the products and the reactants both stay at a constant after some time. When they are constant, this is at Equilibrium
Catalysts Shorten the time to reach equilibrium but Doesn't alter it