Chapter 6 Flashcards
Reaction Quotient (Q)
Q = [reactants]/[prodcuts]
Equilibrium
Q = Keq (forward) = 1/Keq (reverse)
∆G = 0
Equal forward and reverse rates of reaction
Forward Reaction
Q < Keq
Greater concentration of reactants and smaller concentration of products
Forward rate increased to restore equilibrium
Reaction proceeds toward reactants (left)
∆G = +
Reverse Reaction
Q > Keq
Greater concentration of products and smaller concentration of reactants
Reverse rate increased to restore equilibrium
Reaction proceeds toward products (right)
∆G = -
Equilibrium Constant Expression
Pure solids and liquids aren’t included
Temperature dependent!!
Equilibrium Constant Expression Gases
Changes in pH
[H+] decreases with increasing pH
* Shifts reaction to the right
[H+] increases with decreasing pH
* Shifts reaction to the left
Changes in Pressure
Decreasing pressure, shifts reaction to the side with more moles of gas
Increasing pressure shifts reaction to the side with less moles of gas
Changes in Temperature
Increasing temperature shifts reaction based on enthalpy of reaction
If reaction is endothermic (∆H > 0) heat functions as reactant
If reaction is exothermic (∆H < 0) heat functions as product
Decide endothermic exothermic based on where + heat is
Temperature increases, reaction will shift left
Temperature decreases, reaction will shift right
Changes in Water Concentration
Removing water causes reaction to shift to the side where water was previously
All other concentrations would increase proportionately
If now more products than reactants (Q will increase)
If now more reactants than products (Q will decrease)
Kinetic Products
Favored at low temperatures with low heat transfer and short reaction time
Pathway:
* Smaller gain in free energy to reach transition state
* Higher free energy of products
* Smaller difference in free energy between transition state and products.
Thermodynamic Products
Favored at high temperatures with high heat transfer and long reaction time
Pathway:
* Higher gain in free energy to reach transition state
* Smaller free energy of products
* Higher difference in free energy between transition state and products (more stable)
Changes in Volume
Decreasing volume causes shift to side with less moles of gas
Increasing volume causes shift to side with more moles of gas
