Chapter 6, Problem 6.1E

When two systems are in contact, the entropy transfer from the warmer system is equal to the entropy transfer into the cooler one at the point of contact. That is, no entropy can be created or destroyed at the boundary since the boundary has no thickness and occupies no volume.

Answer true (T) or false (F) as appropriate1. Entropy is a measure of irreversibilities in processes.2. The entropy of the universe must always decrease.3. The thermal efficiency of a Carnot engine is the maximum possible.4. The gas turbine operates on the Rankine cycle.5. The steam turbine operates on the Brayton cycle.

answer the following true or false. (a) A process that violates the second law of thermodynamics violates the first law of thermodynamics. (b) When a net amount of work is done on a closed system undergoing an internally reversible process, a net heat transfer of energy from the system also occurs. (c) A closed system can experience an increase in entropy only when a net amount of entropy is transferred into the system. (d) The change in entropy of a closed system is the same for every process between two specified end states.

Answer the following true or false. Explain. (a) A process that violates the second law of thermodynamics violates the first law of thermidynamics. (b) When a net amount of work is done on a closed system undergoing an internally reversible process, a net heat transfer of energy from the system also occurs. (c) One corollary of the second law of thermodynamics states that the change in entropy of a closed system must be greater than zero or equal to zero. (d) A closed system can experience an increase in entropy only when irreversibilities are present within the system during the process. (e) Entropy is produced in every internally reversible process of a closed system. (f) In an adiabatic and internally reversible process of  a closed system, the entropy remains constant. (g) The energy of an isolated system must remain constant, but the entropy can only decrease.

Steam enters a turbine operating at a steady state at a pressure of 4 MPa, at temperature of 400 degrees Celcius, and a velocity of 200m/s . Saturated vapor exits at 100 degrees Celcius with a velocity of 100 m/s. Heat transfer from the turbine to its surroundings takes place at the rate of 20 kJ/kg of steam at a location where the average surface temperature is 350K. (a) Write the energy and entropy balance equations for a control volume the includes only the turbine and its contents (b) Determine the work produced, in kJ/kg of steam flowing. (c) For a control volume that includes only the turbine and its contents, calculate the rate of entropy production in kJ/kg*K (d) Assume the turbine described above is located in a factory where  the ambient temperature is 27 degrees Celcius. Determine the rate of entropy production in kj/kg*Kof steam, for an inlarged control volume that included the turbine and enough of its immediate surroundings so that heat transfer takes place from the…

2. Please consider a universe that consisted of two very, very large bodies that exchanged 1,000 Btu. The first body was at 1,000 R. Please determine the change in entropy of (1) each body and (2) of the universe (in Btul R) if the second body was at a. 200 •R. b. 500 R c. 1,000 R.

Data are provided for steady-state operation of an electric motor in figure below, where hA = 5 W/K.   Determine for the motor the rate of entropy production, in W/K.

Explain into details why thermodynamics depends on the entropy?

Find the cycle entropy production and answer if it operates irreversibly, reverisbly, or impossibly. A system executes a power cycle while receiving 1000 kJ by heat transfer at a temperature of 500 K and discharging energy by heat transfer at 300 K. Determine the cycle entropy production if the cycle thermal efficiency is 25% in kJ / K. Enter the answer without units, but with a minus sign if applicable. This cycle operates     irreversibly     reversibly     impossibly.