Study Set Content:
When a mixture of reactants and products of a reaction reaches equilibrium at a given temperature, its reaction quotient always has the same value.
equilibrium constant
is achieved when the rates of the forward and reverse reactions are equal and the concentrations of the reactants and products remain constant.
Chemical Equilibrium
: When a reaction has attained equilibrium at a given temperature, the reaction quotient for the reaction always has the same value.
Law of Mass Action
When a mixture of reactants and products of a reaction reaches equilibrium at a given temperature, its reaction quotient
always has the same value
As for the reaction quotient, when evaluated in terms of concentrations, it is noted as
Kc
forward and reverse reaction occur at same rate
Dynamic process
Solids and liquids DO NOT appear in the expression
HETEROGENEOUS EQUILIBRIA
• Reactants and products are in different phases
HETEROGENEOUS EQUILIBRIA
Qc=Kc
All reacting species are in the same phase
HOMOGENEOUS EQUILIBRIA
• For gaseous reactions, use
partial pressure
To determine the direction in which the net reaction will proceed to achieve equilibrium, we compare the values
Qc and Kc .
states that if an external stress is applied to a system at equilibrium, the system adjusts in such a way that the stress is partially offset as the system reaches a new equilibrium position.
Le Chatelier’s Principle
French chemist. did work on metallurgy, cements, glasses, fuels, and explosives. He was also noted for his skills in industrial management
Henri Louis Le Châtelier
means a change in concentration, pressure, volume, or temperature that removes the system from the equilibrium state
stress
Factors that affect chemical equilibrium
Changes in concentration
Pressure change
Changes in Temperature
Effect of a catalyst
When more reactant is added to, or some product is removed from, an equilibrium mixture, thereby changing the concentration of reactant or product
net reaction occurs left to right
When more product is added to, or some reactant is removed from, an equilibrium mixture, thereby changing the concentration of reactant or product
net reaction occurs right to left(reverse direction)
the amounts of products are increased at equilibrium by a decrease in temperature.
exothermic reaction
left
