1 A sample of NH4HS(s) is placed in a 2.58L flask containing 0.100 mol of NH3(g). NH4HS(s) ⇌ NH3(g) + H2S(g) KP = 0.108 at 25°C What will be the total gas pressure when equilibrium is established at 25°C? 2 A solution is prepared with [V3+] = [Cr2+] = 0.0100 M and [V2+] = [Cr3+] = 0.150 M. The following equilibrium is established: V3+(aq) + Cr2+(aq) ⇌ V2+(aq) + Cr3+(aq) KC = 7.2 x 102 What are the ion concentrations when equilibrium is established? 3 The N2O4, NO2 equilibrium mixture in the flask on the left in the figure is allowed to expand into the evacuated flask on the right. N2O4 (g) ⇌ 2NO2(g) KC = 4.61 x 10-3 at 25°C What is the composition of the gaseous mixture when equilibrium is reestablished in the system consisting of the two flasks? 4 Cadmium metal is added to 0.350 L of an aqueous solution in which [Cr3+] = 1.00 M. What are the concentrations of all ions at equilibrium? 2Cr3+(aq) + Cd(s) ⇌ 2Cr2+(aq) + Cd2+(aq) KC = 0.288 What is the minimum mass of cadmium metal needed to establish this equilibrium? 5 Lead metal is added to 0.100 M Cr3+(aq). What are the concentrations of all ions at equilibrium? 2Cr3+(aq) + Pb(s) ⇌ 2Cr2+(aq) + Pb2+(aq) KC = 3.2 x 10-10 6 Nitrogen dioxide obtained as a cylinder gas is always a mixture of N2O4 and NO2. A 5.00 g sample obtained from such a cylinder is sealed in a 0.500 L flask at 298 K. What is the mole fraction of NO2 in this mixture? N2O4 (g) ⇌ NO2(g) KC = 4.61 x 10-3