Chapter 6, Problem 6.45P

A divider separates 1 lb mass of carbon monoxide (CO) from a thermal reservoir at 150o F. the carbon monoxide, initially at 60o F  and 150 lbf/in2, expands isothermally to a final pressure of 10 lbf/in2 while receiving heat transfer through the divider from the reservoir. The carbon monoxide can be modeled as an ideal gas. (a) For the carbon monoxide as the system, evaluate the work and heat transfer, each in Btu and the amount of entropy produced, in Btu/oR. (b) Evaluate the entropy production, in Btu/oR, for an enlarged system that includesthe carbon monoxide and the divider, assuming the state of the divider remains unchanged. Compare with the entropy production of part (a) and comment on the difference.

Refrigerant 134a at p1 = 30 lbe/in?, T1 = 40°F enters a compressor operating at steady state with a mass flow rate of 400 Ib/h and exits as saturated vapor at p2 = 160 Ib/in?. Heat transfer occurs from the compressor to its surroundings, which are at To = 40°F. Changes in kinetic and potential energy can be ignored. The power input to the compressor is 4 hp. Determine the heat transfer rate for the compressor, in Btu/hr, and the entropy production rate for the compressor, in Btu/hr.°R.

A container of 1.5 Kg of gas is at a temperature and pressure of 293 K and 1 bar respectively.   The gas is adiabatically compressed until its temperature and pressure are 450 K, 4.49 bars.  Adiabatic processes are processes with no heat transfer.  The properties of this gas are cv = 10.3 KJ/(Kg K) and R = 4.158 KJ/(Kg K).  Neglect kinetic and potential energy terms.    Use the first law to determine the work into the system. Calculate the entropy production for this process. Is this a reversible process?

Refrigerant 134a at p1 = 30 lbş/in?, T1 = 40°F enters a compressor operating at steady state with a mass flow rate of 250 lb/h and exits as saturated vapor at p2 = 160 lbę/in?. Heat transfer occurs from the compressor to its surroundings, which are at To = 40°F. Changes in kinetic and potential energy can be ignored. The power input to the compressor is 2.5 hp. Determine the heat transfer rate for the compressor, in Btu/hr, and the entropy production rate for the compressor, in Btu/hr-°R.

Carbon dioxide (CO₂) fills a closed, rigid tank fitted with a paddle wheel, initially at 80°F, 30 lb-/in², and a volume of 1.8 ft³. The gas is stirred until its temperature is 500°F. During this process heat transfer from the gas to its surroundings occurs in an amount 2.6 Btu. Assume ideal gas behavior, but do not assume constant specific heats. Kinetic and potential energy effects can be ignored. Determine the mass of the carbon dioxide, in lb, and the work, in Btu.

The entropy of an ideal gas depends on both T and P. The function s° represents only the temperature-dependent part of entropy.

Consider a piston-cylinder assembly containing 10.0 kg of water. Initially, the gas has a pressure of 20.0 bar and occupies a volume of 1.0 m3. The system undergoes a reversible process in which it is compressed to 100 bar. The pressure volume relationship during this process is given by: PV1.5 = constant. (a) What is the initial temperature? (b) Calculate the work done during this process. (c) Calculate the heat transferred during this process. (d) What is the final temperature?

Argon (molar mass 40 kg/kmol) compresses reversibly in an adiabatic system from 5 bar, 25 0C to a volume of 0.2 m3. If the initial volume occupied was 0.9 m3, calculate the work input in MJ to 3 decimal places. Assume nitrogen to be a perfect gas and take cv = 0.3122 k J / k g K.

The entropy change of a system can be negative, but the entropy generation cannot.