Oxygen (O2) gas within a piston-cylinder assembly undergoes an expansion from a volume V1 = 0.01 m3 to a volume V2 = 0.03 m3. The relationship between pressure and volume during the process is P = AV-1 + B, where A = 0.06 bar m3, and B = 3.0 bar. For the O2 , determine the following:
a.) The initial and final pressures, each in bar.
b.) The work, in kJ.
5 comments:
ANSWERS:
P2 = 5.0 bar
W = +/- 12.59 kJ (YOU determine the sign)
HINT:
b) Plug the relationship for P into the boundary work integral (P dV) and then do the integral.
Tried solving this question. didnt get the answer.Is the constant A in bar m3 or is it an error in the question.. please i would love to see how you solved it despite the hints you gave cause am not getting the answer....
I apologize Ebudo. This problem statement is not correct. My colleague used this problem and I not sure what she meant here. I hope the rest of this blog is helpful to you.
sigh of relief, thought i was the one with the problem..thanks..Dr P please can you help explain how i can go about the problem am about to ask: 1 kg of a fluid expands reversibly according to a linear law from 4.2bar to 1.4bar;the initial and final volumes are 0.004m3 and 0.2m3.The fluid is then cooled reversibly at constant pressure,and finally compressed reversibly acording to a law pv=constant back to the initial conditions of 4.2bar and 0.004m3.Calc the workdone in each process. am confusd on what it means to expand according to a linear law, how do i solve it each stage....pls help!!!!
Hi Ebudo,
I am Dr B!
I agree with you that the phrase "a fluid expands reversibly according to a linear law" is confusing. It MIGHT mean that the process path is linear on a PV diagram, but I am not certain. Once you resolve this question, the problem should be fairly easy to solve. Check out my example problem here:
http://www.learnthermo.com/examples/ch04/p-4a-1.php
Best of luck !
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