solve the above questions. For the process diagrammed below, p1 = 670 kPa, p2 =
ID: 788728 • Letter: S
Question
solve the above questions.
For the process diagrammed below, p1 = 670 kPa, p2 = 240 kPa, v l = 0.49 m3/kg, and the process from 1 to 2 is isotherm al. If the sample is 3.4 kg o f gaseous propane, find the net work done in going from state 1 to state If the process returns the system to its original state via an isochoric process followed by an isobaric one, what is the net work done in the cycle? If the process returns the system to its original state via an isobaric process followed by an isochoric one, what is the net work done in the cycle? A mass of 2.2 kg of air at 6283 kPa and 208 oC is contained in a gas-tight frictionless piston-cylinder. The gas is expanded to a final pressure of 1232 kPa in an isothermal process. Calculate the work done (output positive) in the process. A mass of 3.5 kg of water at 1698 kPa and 2741 oC is contained is a gas-tight frictionless piston-cylinder. The gas is compressed to a final pressure of 6978 kPa in a polytropic process where n = 1.32. Calculate the work done (output positive) in the process.Explanation / Answer
a) workdone=nRTln(V2/V1)
P1V1=n1RT1 ===>T1=670*10^3*0.49*3.4/(3.4*10^3/42)*8.314=1658.48K
p1v1=p2v2 ====>v2=670*0.49/240=1.368 m3/kg
W=(3.4*10^3/42)*8.314*1658.48*ln(1.368/0.49)=1.146*10^6 J
b)in isochoric w=0
isobaric w=P1(V2-V1)=670*10^3*(1.638-0.49)*3.4=2.615*10^6 J
total W=2.615*10^6 J
c)isobaric w=P2(V2-V1)=240*10^3*(1.638-0.49)*3.4=0.937*10^6 J
in isochoric w=0
total W=0.937*10^6 J
2)workdone=nRTln(V2/V1) substitute values
3)W = [(PV)_2 - (PV)_1]/ (1-n) where n=1.32
substite values
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