1. Reaction Quotient – Q Value of the equilibrium expression for a reaction that is not at equilibrium
3 H2 + N  2 NH Kc = 9.60 at 600 C
What is the value of the reaction quotient Q if you have the
following mixture:
[N2] = 0.50 M; [H2] = 0.80 M; [NH3] = 0.60 M
Q = [NH3] = (0.60) =
[H2] 3 [N2] (0.50) 3 (0.80)
The reaction is not at equilibrium. Q = K at equilibrium

2. 3 H2 + N  2 NH Kc = 9.60 at 600 C
What is the value of the reaction quotient Q if you have the
following mixture:
[N2] = 0.50 M; [H2] = 0.80 M; [NH3] = 0.60 M
Q = [NH3] = (0.60) =
[H2] 3 [N2] (0.50) 3 (0.80)
Will the mixture described above produce more product?
Since Q is less than K, more product will be produced until
Q equals the K value.

3. Given the following reaction: N2 + O2  2 NO Kc = 1
Given the following reaction: N O2  NO Kc = 1.0 x 10 –5 at 1500 K An evacuated 0.50 L chamber is filled with moles of nitrogen and moles of oxygen and heated to 1500 K. What would be the concentration of nitrogen monoxide at equilibrium ?
N O   NO
Initial (M)
Change (M) x x x
Equil. (M) – x  – x  x
1.0 x 10 –5 = [2x] 2
(0.8) (0.2)
x = 6.3 x 10 –4
NO = 2(6.3 x 10 –4) = M

4. Given the following reaction: N2 + O2  2 NO Kc = 1
Given the following reaction: N O2  NO Kc = 1.0 x 10 –5 at 1500 K A 0.50 L chamber contains moles of nitrogen, moles of oxygen, and moles of nitrogen monoxide at 1500 K. Is the mixture at equilibrium. If not, who will the mixture change?
The mixture is at equilibrium if Q equals K.
Q = [NO] = [0.100] =
[N2] [O2] (0.8) (0.2)
Q is larger than K so the mixture is not at equilibrium. More
reactants will be formed as the mixture moves toward
equilibrium.