*3.21. At 100 C 200 g of mercury are added to 80 g of water at 20 C in a vessel that has a water equivalent of 20 g. The specific heat capacities of water and mercury -i may be taken as constant at 4.18 and 0.140 J K respectively. Calculate the entropy change of (a) the mercury; (b) the water and vessel; (c) the mercury, water, and vessel together.