Work calculation for isothermal compression

Click For Summary
SUMMARY

The discussion centers on calculating work done during isothermal compression of an ideal gas using the formulas W=n*R*T*ln(V_f / V_i) and W=p*(V_f - V_i). The user initially attempted to apply the ideal gas equation with specific values (n=1, R=8.31, T=273.15, V_f=17.5 L, V_i=24 L) but encountered errors. Further attempts with the constant-pressure formula also failed, leading to confusion regarding the work of an external agent versus the gas itself. A critical observation highlighted that the provided data does not align with the ideal gas law, indicating a potential error in the problem's parameters.

PREREQUISITES
  • Understanding of ideal gas laws and equations
  • Familiarity with thermodynamic processes, specifically isothermal and constant-pressure processes
  • Knowledge of the properties of gases, including pressure, volume, and temperature relationships
  • Basic algebra for manipulating equations and solving for unknowns
NEXT STEPS
  • Review the ideal gas law and its applications in thermodynamics
  • Study the concept of work done by gases in different thermodynamic processes
  • Learn about the implications of external work in gas compression scenarios
  • Examine the conditions under which the ideal gas law holds true and common exceptions
USEFUL FOR

Students studying thermodynamics, physics educators, and anyone involved in understanding gas behavior under varying conditions.

PNGeng
Messages
17
Reaction score
0

Homework Statement


10i6kx4.png



Homework Equations


Work done by an ideal gas, isothermal process: W=n*R*T*ln(V_f / V_i)
Work, constant-pressure process: W=p*(V_f - V_i)

The Attempt at a Solution


I first tried plugging n=1, R=8.31, T=273.15, V_f=17.5 L, V_i=24 L into the first equation and it didn't work.

I then tried the constant-pressure formula with the corresponding values given from the problem (p=.937 atm, V_f=17.5 L, V_i=24 L) and it didn't work either.

This problem seems pretty straight forward but I can't get the right answer. Help?
 
Physics news on Phys.org
The work formula you used is for the work of the gas. The problem asks the work of an external agent. Is the external work positive or negative?

The data given are not consistent with the ideal gas law. 1 mol oxygen at 0 °C can not have 24 L volume at 0.937 atm pressure. Have you copied it correctly?

ehild
 

Similar threads

Replies
14
Views
2K
Replies
1
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
Replies
12
Views
2K
Replies
4
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 4 ·
Replies
4
Views
1K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 8 ·
Replies
8
Views
6K