Equilibrium WS
1. What effect does a catalyst have on the rate of a reaction?
               How would it affect the activation energy and why?
 
2. For the following equilibria, explain how the given stress affects the equilibrium point.
               a. N2(g)   +   O2 (g)   D   2 NO(g)   Stress: Increase in pressure
               b. 2 SO3 (g)   +   Heat   D   2 SO2 (g)   + O2 (g)  Stress: Increase in Temperature
               c. 2 SO3 (g)   +   Heat   D   2 SO2 (g)   + O2 (g)   Stress: Increase in Pressure
               d. CaCO3(s) D   CaO(s)   +   CO2(g)   Stress: Removal of CO2
 
3. Write the Keq expressions for the following reactions:
               a. 2 C2H6 (g)   +   7 O2 (g) D   4 CO2 (g)   +   6 H2O(g)
               b. 4 PH3 (g) + 3O2   D   P4 (g)  +   6 H2O(g)
               c. 4 HCl(g)   +   O2 (g) D   2 Cl2 (g)   +   2 H2O(g)
 
4. At a high temperature the following system reaches equilibrium
                               N2 + O2   D   2 NO
An analysis of the mixture in a one liter container gives the following results:
nitrogen = 0.50 moles, oxygen = 0.50 moles, nitrogen monoxide = 0.020 mol.
               a. Calculate Keq for this system.
 
   b. At the same temperature, a new system is made with 0.70 moles of each of
   the reactants. Find the concentration of the NO. (Hint: you can use the same
   Keq from part a), why?) 
 
   8. If the Keq for the following reaction is 8.2 x 10-2, find the concentration of
   COCl2 (g) if each product has a concentration of 1.2 x 10-2 M?
                               COCl2 (g) D  CO(g)   +   Cl2 (g) 
 
5. Find the Keq for the reaction if [H2S] = 0.015 M, [H2] = 0.010 M, and the [S2] = 0.051 M.
               2 H2S(g) D   2 H2 (g)   +   S2 (g) 
 
6. In a 1.00 L container, 1 mole of SO3 is decomposed. At equilibrium, 0.300 mole of O2
is present. Calculate the concentrations of SO2 and SO3 at equilibrium, and calculate Keq.
               2 SO3 (g) D   2 SO2 (g)   + O2 (g) 
 
7. A mixture at equilibrium at 827 °C contains 0.552 M CO2, 0.552 M H2, 0.448 M CO, 
and 0.448 M H2O.
                               CO2   +   H2  D   CO   +   H2O
               a. What is the value for Keq at this temperature?
 
               b. More CO2 is added to the system, which direction will the reaction shift?
 
               c. What effect did part b) have on the equilibrium constant?
 
               d. What effect would adding a catalyst have on the equilibrium?
 
               e. Are the reactants or products favored in this reaction?