CHM 1046 Unit 1 Work Sheet
Palmer Graves, Ph.D.
Spring 1999

ANSWERS


1. Kc for a reaction is 160. Solve for the value of Kp for the following reaction at 30°C.

A (g) + 2 B (g) ---> C (g)




2. The equilibrium pressures for N2 and H2 respectively are as follows 0.928 and 0.432. If Kp = 1.45 x 10-5 at 500°C what is the partial pressure of NH3?

N2 (g) + 3 H2 (g) <===> 2 NH3 (g)




3. Write the equilibrium expression for the reaction:

SnO2 (s) + 2 CO (g) <---> Sn(s) + 2 CO2 (g)



What is the value of Kc if the concentrations are all tripled?





4. A gas vessel is charged with a mixture of PCl3 and Cl2 and allowed to equilibrate at 450 K. At equilibrium the partial pressures of the three gases are PPCl3 = 0.124, PCl2 = 0.157, and PPCl5 = 1.30 atm. What is the value of Kp.





5. Consider the reaction:

2 SO2 (g) + O2 (g) <==> 2 SO3 (g)

Which direction would the following changes make the reaction shift:

a. PT decrease
b. PSO2 increase
c. Adding a catalyst


6. Find the rate equation including k for the reaction:
2 NO (g) + O2 (g) ---> 2 NO2 given the following data.

[NO] M [O2]M Initial Rate (M/s)
0.0126 0.0125 0.0141
0.0252 0.0250 0.113
0.0252 0.0125 0.0564





7. The thermal decomposition of N2O5 (g) to form NO2 (g) and O2 (g) is a first-order reaction. The rate constant for the reaction is 5.1 x 10-4 s at 318 K.

a. What is the half-life for this process.



b. If the initial concentration of N2O5 (g) is 0.250 M, what is the concentration after 10 seconds?





8. The activation energy for a process is 76.7 kJ/mol. How many times faster will the reaction occur at 50°C than at 0°C.








9. The reaction listed below is a second order process. Find the concentration after 5.00 minutes if k=1.25 x 10-2M-1min-1 and the initial concentration of A is 0.0125M

A + 2 B -----> C





10. What are the units of k for the following reaction?

Rate = k [A][B]-2 [C]0