(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

The figure shows a thermodynamic process followed by 130 mg of helium. How much work is done on the gas during each of the three segments?

[tex]p_1 = 1.08 atm, p_2 = 5.41 atm, p_3=1.08 atm[/tex]

[tex]T_1=133 C, T_2=T_3=1760 C[/tex]

[tex]V_1=V_2=1000 cm^3, V_3=5000 cm^3[/tex]

These are answers to previous parts of the question that I've been able to work out and have been marked correct by Mastering Physics. I've also attached a picture of the figure for reference, but 1→2 is isochoric, 2→3 is isothermal and 3→1 is isobaric.

2. Relevant equations

[tex]-\int_{V_i}^{V^f} p dV[/tex]

W=0, isochoric process

[tex]W= -p \Delta V[/tex] for an isobaric process

[tex]W= -p_iV_i ln(\frac {V_f} {V_i})[/tex] for an isothermal process.

3. The attempt at a solution

[tex]W_1→2 = 0[/tex] because it's an isochoric process. Hooray, easy!

[tex]W_2→3 =-p_2V_2 ln(\frac {V_3} {V_2})=-5.41*.001*ln(\frac {.005} {.001}) = -0.0087[/tex]

[tex]W_3→1 = -p \Delta V=-1.08*(.001-.005)=0.00432[/tex]

So, my answers to the work from 2→3 and 3→1 are not right. Because I'm redoing the problems for practice, I know what the correct answers are, but I've been unable to back solve my way into them.

Any help as to where I'm going awry would be greatly appreciated!

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# Homework Help: Calculating work done in a thermodynamic process

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