Name:__________________________________
Equilibrium/Le Chat Review
On a separate piece of paper, do the following:
1. Write the expression for the equilibrium constant (Keq) for each of the reactions given.
a. N2(g) + 3H2(g) ↔ 2NH3(g)
b. 2KClO3(s) ↔ 2KCl(s) + 3O2(g)
c. H2O(l) ↔ H+1(aq) + O-1 (aq)
d. 2CO(g) + O2(g) ↔ 2CO2(g)
e. Li2CO3(s) ↔ 2Li+1(aq) + CO3-2(aq)
f. 2NO2(g) ↔ N2O4(g)
g. 2BrNO(g) ↔ 2NO(g) + Br2(g)
h. H2O(l) + HF(aq) ↔ H3O+1(aq) + F-1(aq)
2. Consider the following reaction: 2H2S(g) ↔ 2H2(g) + S2(g) . Find the mistakes in the
following equilibrium expression, fix them, and explain. Keq = [H2] [S2] / [H2S]
3. Consider the following reaction: CO(g) + Cl2(g) ↔ COCl2(g) . Find the mistakes in the
following equilibrium expression, fix them, and explain. Keq = [CO] [Cl2] / [COCl2]
4. Go back to Question 1 and calculate the value of Keq for each reaction when given the
following concentrations:
a. [N2]=0.0200 M, [H2]=0.0200 M, [NH3]=0.0100 M
b. [O2]=0.0500 M
c. [H+1]=1x10-8 M, [OH-1]=1x10-6 M
d. [CO]=2.0 M, [O2]=1.5 M, [CO2]=3.0 M
5. For each of the following equilibrium constants, indicate whether you would expect an
equilibrium reaction mixture to be dominated by reactants, dominated by products, or to
contain significant amounts of both:
a. 5.2x1017
b. 12.4
c. 3.22x10-21
d. 0.047
e. 0.95
f. 8.5x10-7
g. 1.4x1019
6. An equilibrium mixture of the following reaction (SbCl5(g) ↔ SbCl3(g) + Cl2(g) ) was found
to have [SbCl3]=0.0298 M and [Cl2]=0.105 M at 248 deg C. Keq at 248 deg C = 4.9x10-4.
What is the concentration of the SbCl5?
20. Fill out the tables below, using Le Chatelier’s Principle for the following reactions:
N2(g) + 3H2(g) ↔ 2NH3(g) + heat
Stress
Direction of
Shift
[N2]
[H2]
[NH3]
Add N2
Add H2
Remove N2
Remove H2
Remove NH3
Increase Temp
Decrease Temp
Increase Pressure
Decrease Pressure
Heat + H2(g) + I2(g) ↔ 2HI(g)
Stress
Add H2
Add I2
Add HI
Remove H2
Remove I2
Remove HI
Increase
Temperature
Increase Pressure
Direction of
Shift
[H2]
[I2]
[HI3]