Chapter 5, Problem 5.45CU

Carbon dioxide (CO2) fills a closed, rigid tank fitted with a paddle wheel, initially at 80°F, 50 lbf/in2, and a volume of 2.2 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.

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.

A 300-lb iron casting. initially at 600°F, is quenched in a tank filled with 2121 lb of oil, initially at 80°F. The iron casting and oil can be modeled as incompressible with specific heats 0.10 Btu/lb - °R. and 0.45 Btu/lb - °R, respectively. (a) For the iron casting and oil as the system.determine the final equilibrium temperature, in °F. Ignore heat transfer between the system and its surroundings. °F (b) For the iron casting and oil as the system,determine the amount of entropy produced within the tank, in Btu/°R. Ignore heat transfer between the system and its surroundings. Btu/°R

Carbon dioxide (molar mass 44 kg/kmol) expands reversibly in a perfectly thermally insulated cylinder from 3.7 bar, 220 0C to a volume of 0.085 m3. If the initial volume occupied was 0.02 m3, calculate the work input in kJ to 3 decimal places. Assume nitrogen to be a perfect gas and take cv = 0.63 k J / k g K.

boundaries. Classification of thermodynamic Systems

Which of the following statements correctly completes the sentence: "The state postulate..." states that a system in equilibrium can be fully defined if two independent properties of the system are known. O O O O O ... relates the net heat and work inputs to a system to the change in its internal energy. allows calculation of change in entropy from the heat transfers in a system. states that the work done by a system to with a moving boundary is equal to the area under the process line when plotted on a pV diagram. allows us to convert extensive property values to intensive property values.

Bernoulli's principle is an example of which law of thermodynamics. Explain why?

Carbon dioxide (CO₂) fills a closed, rigid tank fitted with a paddle wheel, initially at 80°F, 50 lb/in², and a volume of 1.6 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. Step 1 Determine the mass of the carbon dioxide, in lb. m = 0.60792 Hint Your answer is correct. Step 2 * Your answer is incorrect. Determine the work, in Btu. W12= -53.4318 eTextbook and Media Hint lb Btu Attempts: 1 of 4 used Assistance Used

Heat transfer is always from higher reservoir to a lower reservoir, and not the opposite, because: Higher energy means more capability to diffuse Higher energy means capability to be constant Higher energy means atoms and molecules are in ground state Lower energy means system is in equilibrium None of the above