Initially, an insulated rigid tank contains 18.67 kg of water at 21.45oC and 101 kPa. The tank also contains a 3.66 kg copper block at 83.32oC. Assume constant specific heats where Cwater = 4.179 kJ/kg-K and CCu = 0.385 kJ/kg-K. Determine the total entropy production (kJ/K) after one hour assuming thermal equilibrium is achieved.