Dougherty Valley HS Chemistry
Equilibrium Worksheet
One point deducted if numerical final-answers are not boxed.
Name:
Date:
Period:
1. Explain the differences between equilibrium constant (Keq) and solubility product constant (Ksp).
2. Why are solids and liquids not included in Keq expressions?
3. Write the Keq expressions for the following reactions:
4H3O+ (aq) + 2Cl- (aq) + MnO2 (s)  Mn2+ (aq) + 6H2O (l) + Cl2 (g)
Solid phosphorus pentachloride is decomposed to liquid phosphorus trichloride and chlorine gas.
CO2 (g) + MgO (s)  MgCO3 (s)
4. Suppose that for the unbalanced reaction: __N2 (g) + __Cl2 (g)  __NCl3 (g) it is determined that, at a
particular temperature, the equilibrium concentrations are [N2 (g)] = 0.000104M, [Cl2 (g)] = 0.000201M,
and [NCl3 (g)] = 0.141M. Calculate the value of Keq for the reaction at this temperature.
5. Gaseous phosphorus pentachloride decomposes to chlorine gas and gaseous phosphorus trichloride. In a
certain experiment, at a temperature where Keq = 8.96E-2, the equilibrium concentrations of PCl5 and Cl2
were found to be 5.67E-3M and 0.233M, respectively. Calculate the concentration of PCl3 present at
equilibrium.
6. For the unbalanced reaction: __N2 (g) + __H2 (g)  __NH3 (g) show your calculations for Keq given
the following equilibrium concentrations during each of the 3 experiments below:
Experiment I: [N2] = 0.921M
[H2] = 0.763M
[NH3] = 0.157M
Experiment II:
[N2] = 0.399M
Experiment III: [N2] = 2.59M
[H2] = 1.197M
[NH3] = 0.203M
[H2] = 2.77M
[NH3] = 1.82M
7. In the previous problem, what does the value of Keq tell about the relative concentrations of the reactants
versus the products at equilibrium? Explain why. (Hint: Large vs. small)
8. Write the balanced equation for the dissociation of the following solids in water. Also, write the Ksp
expression for each solid.
[a] Plumbous chloride (s)
[b] silver dichromate (s)
[c] strontium phosphate (s)
9. The Ksp value for Plumbous arsenate (s) is 4.1E-36 at 25°C. Calculate the solubility of Plumbous arsenate (s)
in water at 25°C.
10. Given the reaction: ___NH3 (g) + ___O2 (g)
 ___NO (g) + ___H2O (g) + energy
Determine the direction of shift resulting from each applied stress. Explain your reasoning:
A. addition of NO (g)
B. removal of O2 (g)
C. increase the pressure by decreasing the volume
D. decreasing the temperature
E. adding a catalyst