How to Calculate Work for Isothermal Processes with a Non-Ideal Gas?

  • Thread starter Thread starter opprobe
  • Start date Start date
  • Tags Tags
    Isothermal
Click For Summary
SUMMARY

The discussion focuses on calculating work for isothermal processes involving a non-ideal gas, governed by the equation of state PV=RT/(1-bP). The derived formula for work, W=(P1V1-P2V2)+RTln[(P22V2)/(P12V1)], is confirmed through integration techniques. The user initially struggled with integrating the pressure expression and received guidance to use integration by parts, which proved effective in solving the problem.

PREREQUISITES
  • Understanding of thermodynamics, specifically isothermal processes
  • Familiarity with the ideal gas law and non-ideal gas behavior
  • Knowledge of calculus, particularly integration techniques
  • Experience with mathematical software like Wolfram for complex calculations
NEXT STEPS
  • Study the derivation of work done in isothermal processes for ideal and non-ideal gases
  • Learn advanced integration techniques, including integration by parts
  • Explore the implications of the temperature-dependent constant 'b' in real gas behavior
  • Investigate the applications of the equation of state PV=RT/(1-bP) in thermodynamic systems
USEFUL FOR

Students and professionals in thermodynamics, physicists, and engineers focusing on non-ideal gas behavior and isothermal processes.

opprobe
Messages
17
Reaction score
0

Homework Statement


Gas obeys Equation of State, PV=RT/(1-bP), where b is a temperature dependent constant.
Isothermal process (T is constant)
V goes from V1 to V2
P goes from P1 to P2

Show that the amount of Work is
W=(P1V1-P2V2)+RTln[(P22V2)/(P12V1)

Homework Equations


W=-∫P(V)dV
ΔU=Q+W

The Attempt at a Solution


Solved PV=RT/(1-bP) for P in terms of V
P=(-1\pmSqrt[1-4bRT/V])/(2b)

I don't know how to really integrate that expression. I used Wolfram to eventually get this expression:

∫P(V)dV=-V/(2b)\pmRTln(2V(Sqrt[1-4bRT/V]+1)-4bRT)-V*Sqrt[1-4bRT/V]

I'm pretty sure that this isn't the approach to solve this problem. Can someone point me in the right direction?

Thanks in advance!
 
Physics news on Phys.org
Try integrating PdV by parts.

Chet
 
That did it. Thanks for the help!
 

Similar threads

  • · Replies 2 ·
Replies
2
Views
8K
Replies
5
Views
2K
  • · Replies 6 ·
Replies
6
Views
3K
  • · Replies 1 ·
Replies
1
Views
3K
Replies
4
Views
9K
Replies
3
Views
2K
Replies
3
Views
10K
  • · Replies 4 ·
Replies
4
Views
4K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 2 ·
Replies
2
Views
3K