Calculate the entropy change when a. two moles of H2O(g) are cooled irreversibly at constant p from 120°C to 100°C. b. one mole of H2O(g) is expanded at constant pressure of 2 bar from an original volume of 20 L to a final volume of 25 L. You can consider the gas to be ideal. c. one hundred grams of H2O(s) at -10°C and 1 bar are heated to H2O(l) at +10°C and 1 bar.