15 A mixture of 1773 g of water and 227 g of ice is in an initial equilibrium state at 0.000°C. The mixture is then, in a reversible process, brought to a second equilibrium state where the water-ice ratio, by mass, is 1.00:1.00 at 0.000°C. (a) Calculate the entropy change of the system during this process. (The heat of fusion for wa- ter is 333 kJ/kg.) (b) The system is then returned to the initial equi- librium state in an irreversible process (say, by using a Bunsen burner). Calculate the entropy change of the system during this process. (c) Are your answers consistent with the second law of thermodynamics?

A heat engine operates under the following thermodynamic cycle:A→B: isobaric expansion(P=const.)B→C: isochoric cooling(V=const.)C→A: isothermal compression(T=const.)The engine is operated by nmoles of oxygen, a diatomicgas which behaves like an ideal gas without any appreciable vibrational kinetic energy.The thermodynamic cycle described by the gas is entirely defined by pressures PAand PC, and volume VA. Assume that PC=PA/2and give all your answers in terms of n, R, PAand VA. b)Sketch the cycle on a P-Vdiagram and determine all the unknown pressures, volumes and temperatures. c)Determine the efficiency of this engine, defined by e =Wnet/Qin.Wnetis the net work done by the gas over a full cycle and Qinis the total heat that flows into the gas.Be careful, Qindoes not include the heat released by the gas.

When 1.60 ✕ 105 J of heat transfer occurs into a meat pie initially at 20.0°C, its entropy increases by 465 J/K. What is its final temperature (in degrees)? _________ °C

53. What is the decrease in entropy of 25.0 g of water that condenses on a bathroom mirror at a temperature of 35.0° C, assuming no change in temperature and given the latent heat of vaporization to be 2450 kJ/kg?