# Chemical Equlibrium Homework Problem Set

This problem set was developed by S.E. Van Bramer for Chemistry 146 at Widener University.

1. Write an equlibrium expression for each of the following chemical reactions:
1. 3 O2 (g) <--> 2 O3 (g)
2. H2 (g) + I2 (g) <--> 2 HI (g)
3. 2 HI (g) <--> H2 (g) + I2 (g)
4. 4 NH3 (g) + 3 O2 (g) <--> 6 H2O (g) + 2 N2 (g)
5. 2 H2S (g) + 3 O2 (g) <--> 2 H2O (g) + 2 SO2 (g)
6. CaCO3 (s) + CO2 (g) + H2O (l) <--> Ca2+ (aq) + 2 HCO31- (aq)

2. 10 grams of PCl5 is added to a 3.0 liter flask at 250 oC. After the system comes to equlibrium the pressure in the flask is 1.136 x 105Pa.

PCl5 (g) <--> PCl3 (g) + Cl2 (g)

1. What is the equlibrium concentration of each species?
2. What is the partial pressure of each species?
3. What is Kc for this system?
4. What is Kp for this system?

3. Using the equlibrium constant for PCl5 from the previous problem, calculate the equlibrium pressure of each species under the following conditions:
1. 5 grams of PCl5 is added to a 3.0 liter flask at 250 oC.
2. 25 grams of PCl5 is added to a 6.0 liter flask at 250 oC.
3. 5 grams of PCl3 and 5 grams of Cl2 is added to a 3.0 liter flask at 250 oC.

4. The equlibrium constant (Kc) for the reaction SO2 (g) + NO2 (g) <--> SO3 (g) + NO (g) is 9.00 at 973 K. What is the final concentration of all four compounds when:
1. 1.00 mole of SO2 and 1.00 mole of NO2 are injected into a 1.00 liter container at 973 K.
2. 1.00 mole of SO2 and 1.00 mole of NO2 are injected into a 2.00 liter container at 973 K.
3. 1.00 mole of SO3 and 1.00 mole of NO are injected into a 1.00 liter container at 973 K.