Work done by cyclic process (thermodynamics)

AI Thread Summary
The discussion centers on calculating work done by a gas during a cyclic process in thermodynamics. The user seeks clarification on using the ideal gas law (PV=nRT) to determine the number of moles (n) and how to evaluate work under isothermal conditions. It is confirmed that n remains constant and can be derived from the equation, with the user calculating n as 14.440 when T=1. The conversation emphasizes setting pressure and volume conditions equal for both states in the process and integrating to find total work. The integration limits must be correctly ordered to accurately compute the work done.
cpatel23
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Homework Statement


http://s9.postimage.org/5iw5rixyl/image.jpg
(sorry doesn't let me embed)

Homework Equations


P1V1=P2V2
and
PV=nRT

I know that Work done by gas from a --> b = (nRT)*Integral(V2/V1)
My question is do i use PV=nRT to find N? and if T is constant (isothermal) what do I plug in for T when evaluating work?

Using PV=nRT I got n= 14.440 when T=constant (1), is this correct?

I appreciate all of your help.
 
Last edited:
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bump. i really need help.
 
n is constant so you shouldn't need to worry about it.
(PV)/(nRT)=1 for both "a" and "b" so we can set them equal since they both equal 1.
=> P_f*V_f = P_i*V_i
Now you can solve for P_f since everything else is given.
At this point you can integrate from each initial to final (remember to set your integrals limits in the correct order). The total work is the sum of the individual work done on/by the system.
 
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