What is the entropy change for the reaction 2H2(g) + O2(g) 2H2O(l) at 372.2 K and 1.0atm? the enthalpy of reaction at 298.2K and 1.0atm is -572 KJ. The Cp values for H2, O2 and H2O are respectively, 28.8, 29.4, and 75.3 J K mol. (assum that they are constant over this temperature range)