Chapter 6, Problem 6.12P

A rigid cylindrical tank stores 80 kg of a substance at 400 kPa and 480 K while the outside temperature is 290 K. A paddle wheel stirs the system transferring shaft work at a rate of 0.7 kW. At the same time an internal electrical resistance heater transfers electricity at the rate of 1.6 kW. A. Do an energy analysis to determine the rate of heat transfer for the tank. B. Determine the absolute value of the rate at which entropy leaves the internal system (at a uniform temperature of 480 K). Answer in kW/K C. Determine the rate of entropy increase in the system's surroundings. Answer in kW/K

A closed system undergoes a process in which work is done on the system and heat transfer occurs only at a location on the boundary where the temperature is Tb. Considering an adiabatic an internally reversible process, the system entropy change is O positive negative equal to zero O is not predictable from the info given.

A heat pump  design  creates a heating effect  of 35 kW while using 15 kW of electrical power. The thermall energy reservoirs are at 300 K and 250 K. (a) Show the system sketch and label all the values given on it(b) Demonstrate the 1st law application for this system(c) Find entropy generation

The relation of pressure to volume for a closed system undergoing a cyclic reversible process is shown in the figure below. Calculate the net work for the cycle.

The importance of entropy in the analysis of heat engines is a. all of the above b. It is able to show the components that must be present in heat engines c. It enables the computation of the maximum efficiency that a heat engine can achieve d. It is able to express the second law into a mathematical statement

A 15-kg iron block initially at 250°C is quenched in an insulated tank that contains 80 kg of water at 15°C. Assuming the water that vaporizes during the process condenses back in the tank, determine the total entropy change during this process. 2.18 3.28 04.18 1.38 3.18 5.18

Water (2 kg) is in a rigid tank where 22% of the water is in the liquid phase and the temperature is 50 deg C. The tank is heated until all the water is in the vapor phase at a temperature of 120 deg C. This process requires 389 kJ of heat. The wall of the tank is maintained at a constant temperature of 0,4 deg C. What is the entropy produced (kJ/K)? (Report answer to three decimal places)

20 kg of water substance at 10 bar and 500 K is contained in a piston-cylinder apparatus. The system does work and the pressure fall to 1 bar, heat being transferred from a reservoir at 600 K. It is stated that when 3400 kJ of work is done by the apparatus, the final internal energy of the water sustance is 40000 kJ. (a) What is the entropy change (kJ/K) of the water substance? (b) How much heat (kJ) is transferred?

There are two masses of finite size in contact with a constant thermal reservoir. Initially, the masses are separated, with one at a higher, or hotter, temperature (Th) than the other (it is colder, at Te). The hotter mass has a heat capacity C and the colder mass a heat capacity C.. Both masses are in an adiabatic chamber. The masses are slowly brought into contact and thermal equilibrium is reached. Calculate the change in entropy of the system, and show that when Ch = Ce = C, that change is described by the expression: () Th + Tc 2C In 2, ThTc Is this entropy change physically reasonable?