Topic 17 - Chemical Equilibrium Flashcards
Definition of dynamic equilibrium
State in which the rate of the forward reaction equals the rate of the backward reaction
Characteristics of Equilibrium
a) Dynamic
b) Attained in a closed system
c) Constant concentrations of products and reactants
d) No change in macroscopic properties
e) Achieved from any direction
Representation of dynamic equilibrium
ππ΄ +ππ΅ βππΆ +ππ·
Equilibrium constant (Kc) definition
Ratio of concentrations of products over reactants for a reaction that is at equilibrium
Equilibrium constant expression
[C]^π [π·]^π
[π΄]^π [π΅]^π
What does the magnitude of Kc represent?
Position of the equilibrium
Relative amounts of products/reactants
Reaction quotient (Qc) definition
Relative amounts of products and reactants present during a reaction at a particular point in time.
Direction of reaction
(a) Kc = Qc
(b) Kc > Qc
(c) Kc < Qc
(a) Equilibrium
(b) Shifts to the products
(c) Shifts to the reactants
Calculation in Kc for
(a) Inverse reaction
(b) Multiple of a reaction
(c) Adding to reactions
(d) Pure liquids or solids
(a) 1/Kc
(b) [Kc]^n
(c) (K1) (K2)
(d) Eliminate the terms in expression
Formula converting Kc to Kp
Kp = Kc (RT)^βππππ
Predicting when the assumption will be justified to neglect x
[A]o / Kc > 400 | Justified
[A]o / Kc < 400 | Unjustified
Le Chatelierβs Principle
If a dynamic equilibrium is disturbed by changing conditions, the position of the equilibrium shifts to counteract the change to re-establish an equilibrium
Effect of pressure on equilibrium
Increasing pressure shifts the equilibrium to the side with fewer moles of gas
Effect of concentration on equilibrium
Increasing concentration shifts the equilibrium to the side with fewer moles of solute
Effect of catalyst on equilibrium
No change
