A.P. Chemistry
Chapter 15 Equilibrium Problem Set
1. Consider the equilibrium IO4-(aq) + 2 H2O(l)  H4IO6-(aq), Kc = 3.5 x 10-2. If you start with 20.0
mL of a 0.905M solution of NaIO4, and then dilute it with water to 250.0 mL, what is the
concentration of H4IO6- at equilibrium?
2. The hypothetical reaction A + B  C occurs in the forward direction in a single step. The energy
profile is shown in the drawing.
a.
b.
c.
d.
Is the forward or reverse reaction faster at equilibrium?
Would you expect the equilibrium to favor reactants or products?
In general, how would a catalyst affect the energy profile shown?
How would a catalyst affect the ration of the rate constants for the forward and reverse
reactions?
e. How would you expect the equilibrium constant of the reaction to change with
increasing temperature?
3. Write the equilibrium constant expression for the equilibrium:
C(s) + CO2(g)  2 CO(g)
The table included below shows the relative mole percentages of CO2(g) and CO(g) at a total
pressure of 1 atm for several temperatures. Calculate the value of Kp at each temperature. Is the
reaction exothermic or endothermic? Explain.
Temperature (0C)
850
950
1050
1200
CO2(mol %)
6.23
1.32
0.37
0.06
CO (mol %)
93.77
98.68
99.63
99.94
4. Suppose that you worked as the U.S. Patent Office and a patent application came across your
desk claiming that a newly developed catalyst was much superior to the Haber catalyst for
ammonia synthesis because the catalyst led to a much greater equilibrium conversion of N2 and
H2 into NH3 than the Haber catalyst under the same conditions. What would be your response?