Example: Estimate the change in Gibbs free energy for the corrosion of copper metal to cupric ions, by attack by dissolved oxygen in a solution at 25C and pH=3 to form liquid water given that the cupric ion and dissolved oxygen activities are 10-6 mol/kg and 5x10-7 mol/kg, respectively. Recall pH = -log(au-). Species State AG S Cp / J mol-1 / J mol-1 / J mol-1 K-1 |/ J mol-1 K-1 - , 298 1 75.3 g HO HO 02 02 29.4 g aq g H -237178 -228590 0 16320 0 0 0 298610 65700 -285800 -241820 0 -11715 0 0 0 339320 64750 70.0 188.72 205.2 110.9 130.7 0 33.1 166.27 -97.2 28.8 aq 24.4 H+ Cu Cu Cu2+ g a