unit 9 Flashcards
reversible reaction
a reaction that can proceed in both the forward and reverse directions
dynamic equilibrium
the rate of the reverse reaction equals the rate of the forward reaction
(this does not mean that [reactants] and [products] are equal to one another at equilibrium)
Equilibrium constant (K)
Quantifies the relationship between [reactants] and [products] at equilibrium
K = [products]/[reactants]
significance of large K
(K»_space; 1)
forward reaction is favored
-K lies far to right
-high [product] and low [reactant] at equilibrium
-forward reaction proceeds essentially to completion
significance of small K
(K «_space;1)
-reverse reaction is favored
-K lies far to left
-Low [product] and high [reactant] at equilibrium
-Forward reaction does not proceed very far
if you reverse the equation, _ K
invert
what happens to K when you multiply the coefficients in the equation?
raise K by the same factor you multiplied the coefficients
what do you do to K when you add two or more individual chemical equations to each other to obtain an overall equation?
multiply K’s from all equations
What is dynamic equilibrium? Why is it called dynamic?
Rate of the forward reaction = rate of the reverse reaction
Even though [reactants] and [products] remain constant, both the forward and reverse reactions are occurring-reactants and products form at the same rate that they are depleted
What is the significance of the equilibrium constant? What does a large equilibrium constant tell us about a reaction? A small one?
Indicates if the forward reaction (large K) or the reverse reaction (small K) is favored
concentration of gas equation
n/V = P/RT
pressure of a gas and concentration proportion
direct
Kc
equilibrium constant expressed in terms of concentrations of reactants and products
Kp
equilibrium constant for gaseous reactions, expressed in terms of partial pressure in atm
is the partial pressure of a gas in atm the same as the molar concentration of that gas?
no
Kc and Kp are only equal when
there is no change in the number of gas phase particles during the reaction
gas particle change equation
Kp = Kc (RT)^∆n
∆n = mol products - mol reactants
Explain the difference between Kc and Kp. For a given reaction, how are the two constants related?
Kc is the equilibrium constant with respect to concentration in molarity
Kp is the equilibrium constant for gaseous reactions in terms of partial pressures
why don’t pure liquids/solids included in equilibrium expressions?
their concentrations do not change in the course of the reaction
they’re incorporated into values of Kc or Kp
ONLY INCLUDE GASES IN EQUILIBRIUM EXPRESSION