Nitrosyl chloride, NOC1, decomposes to NO and Cl2 at high temperatures. 2 NOCl(g) ⇌ 2 NO(g) + Cl2(g) Suppose you place 2.00 mol NOC1 in a 1.00–L flask, seal it, and raise the temperature to 462 °C. When equilibrium has been established, 0.66 mol NO is present. Calculate the equilibrium constant Kc for the decomposition reaction from these data.

Kc for the decomposition of ammonium hydrogen sulfide is 1.8 104 at 25 C. NH4HS(s) NH3(g) + H2S(g) (a) When the pure salt decomposes in a flask, what are the equilibrium concentrations of NH3 and H2S? (b) If NH4HS is placed in a flask already containing 0.020 mol/L of NH3 and then the system is allowed to come to equilibrium, what are the equilibrium concentrations of NH3 and H2S?

Suppose a reaction has the equilibrium constant K = 1.3 108. What does the magnitude of this constant tell you about the relative concentrations of products and reactants that will be present once equilibrium is reached? Is this reaction likely to be a good source of the products?

Gaseous acetic acid molecules have a certain tendency to form dimers. (A dimer is a molecule formed by the association of two identical, simpler molecules.) The equilibrium constant Kc at 25C for this reaction is 3.2 104. a If the initial concentration of CH3COOH monomer (the simpler molecule) is 4.0 104 M, what are the concentrations of monomer and dimer when the system comes to equilibrium? (The simpler quadratic equation is obtained by assuming that all of the acid molecules have dimerized and then some of it dissociates to monomer.) b Why do acetic acid molecules dimerize? What type of structure would you draw for the dimer? c As the temperature increases would you expect the percentage of dimer to increase or decrease? Why?

Dinitrogen tetroxide, N2O4, is a colorless gas (boiling point, 21C), which dissociates to give nitrogen dioxide, NO2 a reddish brown gas. N2O4(g)2NO2(g) The equilibrium constant Kc at 25C is 0.125. What percentage of dinitrogen tetroxidc is dissociated when 0.0400 mol N2O4 is placed in a 1.00-L flask at 25C?

Write equilibrium-constant expressions Kp for each of the following reactions: a N2O4(g)2NO2(g) b 2NOBr(g)2NO(g)+Br2(g) c 2SO3(g)2SO2(g)+O2(g) d 4NH3(g)+5O2(g)4NO(g)+6H2O(g)

Kc = 5.6 1012 at 500 K for the dissociation of iodine molecules to iodine atoms. I2(g) 2 I(g) A mixture has [I2] = 0.020 mol/Land [I] = 2.0 108 mol/L. Is the reaction at equilibrium (at 500 K)? If not, which way must the reaction proceed to reach equilibrium?

Fluorine, F2, dissociates into atoms on heating. 12F2(g)F(g) The value of Kp at 842C is 7.55 102 What is the value of Kc at this temperature?

12.103 Methanol, CH3OH, can be produced by the reaction of CO with H2, with the liberation of heat. All species in the reaction are gaseous. What effect will each of the following have on the equilibrium concentration of CO? (a) Pressure is increased, (b) volume of the reaction container is decreased, (c) heat is added, (d) the concentration of CO is increased, (e) some methanol is removed from the container, and (f) H2 is added.