Chapter 15 - Chemical Equilibrium Flashcards
When is a reaction at equilibrium?
When a chemical reaction’s forward and reverse processes are occurring at the same rates.
The composition of an equilibrium mixture does not change over time if what occurs?
If temperature is held constant.
What is the Haber Process?
It is how ammonia is produced.
N₂(g) + 3H₂(g) ⇌ 2NH₃(g) + heat
What is the law of mass action?
It states that the rate of a chemical reaction is equal to the concentration of products divided by the concentration of reactants (all raised to the power of their coefficient).
How is the equilibrium constant expression written?
Kc =([D]^d[E]^e)/([A]^a[B]^b)
from: aA + bB ⇌ dD + eE.
What is Kc?
The equilibrium constant, which has no units.
How is Kp calculated?
Kp=[(Pd)^d(Pe)^e]/[(Pa)^a(Pb)^b]
from: a A + b B ⇌ d D + e E.
How are Kc and Kp related (it’s a formula)?
Kp=Kc(RT)^Δn
where R is the ideal gas constant and T is temp. in kelvins.
A large value of Kc indicates what?
That the equilibrium mixture contains more products than reactants.
A small value of Kc indicates what?
That the equilibrium mixture contains more reactants than products.
Given an equilibrium constant (expression) of a forward reaction, how do you calculate the reverse reaction?
The reverse reaction is equal to the reciprocal of the forward reaction. Ex: (5)^-1
What is homogenous equilibria?
It is when substances of the same phase are in equilibrium.
What is heterogeneous equilibria?
It is when substances of different phases are in equilibrium.
What phases are excluded when determining equilibrium?
Solids and liquids
How do you calculate a reaction quotient?
By substituting reactant and product concentrations or partial pressures at any point during a reaction into the equilibrium-constant expression.
