**The following problems are taken from T. L. Brown, H.
E. Lemay, B. E. Bursten, & J. R. Burdge, Chemistry: The Central Science,
Ninth ^{} Edition, Chapter 15. To see the solution to a problem or to
return from the solution, click on the number of the problem.**

12**)** **The equilibrium constant for the reaction**

** 2NO(g) + Br _{2}(g) 2NOBr(g)**

** is K _{eq} = 1.3 x 10^{-2} at 1000 K..**

** (a) Calculate K _{eq} for 2NOBr(g) 2NO(g) + Br_{2}(g)**

** (b) At this temperature does the equilibrium favor NO and Br _{2}, or does it favor NOBr?**

14**)** ** Consider the following equilibrium, for which K _{eq} = 0.0752 at 480°C:**

** 2Cl _{2}(g) + 2H_{2}O(g) 4HCl(g) + O_{2}(g) **

** (a) What is the value of K _{eq} for the reaction 4HCl(g) + O_{2}(g) 2Cl_{2}(g) + 2H_{2}O(g)?**

** (b) What is the value of K _{eq} for the reaction Cl_{2}(g) + H_{2}O(g)2HCl(g) + 1/2O_{2}(g)?**

** (c) What is the value of K _{eq} for the reaction 2HCl(g) + 1/2O_{2}(g)Cl_{2}(g) + H_{2}O(g)?**

22**)** ** Phosphorus trichloride gas and chlorine gas react to form phosphorus pentachloride gas:**

** PCl _{3}(g) + Cl_{2}(g) PCl_{5}(g)**

** A gas vessel is charged with a mixture of PCl _{3}(g) and Cl_{2}(g), which is allowed to equilibrate at 450 K. At equilibrium the partial pressures of the three gases are P_{PCl3} = 0.124 atm, P_{Cl2} = 0.157 atm, and P_{PCl5} = 0.130 atm.**

** (a) What is the value of K _{eq} at this temperature?**

** (b) Does the equilibrium favor reactants or products?**

** **

24**)** ** A mixture of 1.374 g of H _{2} and 70.31 g of Br_{2} is heated in a 2.00-L vessel at 700 K. These substances react as follows: **

** H _{2}(g) + Br_{2}(g) 2HBr(g) **

** At equilibrium the vessel is found to contain 0.566 g of H _{2}. _{} **

** (a) Calculate the equilibrium partial pressures of H _{2}, Br_{2}, and HBr.**

** (b) Calculate K _{eq}. **

** **

32**)** ** At 900 K the following reaction has K _{eq} = 0.345:**

** 2SO _{2}(g) + O_{2}(g) 2SO_{3}(g)**

** In an equilibrium mixture the partial pressures of SO _{2} and O_{2} are 0.165 atm and 0.755 atm, respectively. What is the equilibrium partial pressure of SO_{3} in the mixture?**

38**)** ** At 21.8°C, K _{eq} = 7.0 x 10^{-2} for the equilibrium **

** NH _{4}HS(s) NH_{3}(g) + H_{2}S(g) **

** Calculate the equilibrium partial pressures of NH _{3} and H_{2}S if a sample of solid NH_{4}HS is placed in a closed vessel and decomposes until equilibrium is reached. **