CHM 136 General Chemistry II
Name
Chapter 14 Worksheet, Spring 2009 – Dr. Steel
1. Write the concentration equilibrium constant expression for each reaction.
a. 2 PbS(s) + 3 O2(g) ↔ 2 PbO(s) + 2 SO2(g)
b. CS2(s) + 4 H2(g) ↔ CH4(g) + 2 H2S(g)
2. Assuming that Kp = 8.95×104 at 100 K for the reaction in question 1b, what is the
value of Kc?
3. a. How will the reaction system in question 1a respond if the concentration of O2 is
doubled?
b. How will the reaction system in question 1b respond if some amount of CH4 is
removed form the system while it is at equilibrium?
4. The reaction below has Kp = 2.40×10-4 at -40 °C. What is the partial pressure of NO2
at equilibrium if the equilibrium partial pressure of N2O4 is 2.95 atm?
N2O4(g) ↔ 2 NO2(g)
5. Consider the following equilibrium:
2 HI(g) ↔ H2(g) + I2(g)
If the initial concentration of HI is 0.500 M, but its equilibrium concentration is only
0.136 M, what is the value of Kc for the reaction?
6. At 375 K the equilibrium constant (Kp) for the decomposition of sulfuryl chloride is
2.40. If the initial pressure of SO2Cl2 is 1.90 atm, what will be the equilibrium partial
pressure of each species?
SO2Cl2(g) ↔ SO2(g) + Cl2(g)
7. Iodine and bromine react to form IBr. At 184 °C the reaction has Kc = 120. If you
begin the reaction with 7.40 g of I2 vapor and 6.30 g of Br2 vapor in a 1.00 L
container, what will be the equilibrium concentration of IBr?
Answers:
2
1a) K = [SO 2 ]
c
3
[O2 ]
2
1b) K = [CH 4 ][H 2S]
c
4
[CS2 ][H 2 ]
2) Kc = 6.03×106
3a) The system shifts to the
right, but K is unchanged. 3b) The system shifts to the right, but K is unchanged. 4) 0.0266 atm
5) Kc = 1.79 6) P of SO2Cl2 = 0.65 atm, P of CO2 = P ofCl2 = 1.25 atm
7) 0.0544 M