Irreversible Adiabatic Expansion (Physical Chemistry)

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SUMMARY

The discussion focuses on calculating the final temperature of an ideal monatomic gas during an irreversible adiabatic expansion. Given 0.553 mol of gas with a specific heat capacity at constant volume (CV,m) of 3R/2, the initial conditions are a pressure of 6.25 bar and a temperature of 306 K. The final pressure after expansion is 1.25 bar. The key equation used is CVΔT = -PextΔV, where the ideal gas law is applied to express the final volume in terms of the final temperature, allowing for the determination of ΔT through algebraic manipulation.

PREREQUISITES
  • Understanding of ideal gas laws and equations
  • Knowledge of thermodynamic principles, specifically adiabatic processes
  • Familiarity with the concept of molar specific heat capacities
  • Basic algebraic manipulation skills for solving equations
NEXT STEPS
  • Study the derivation and application of the ideal gas law in thermodynamic processes
  • Learn about adiabatic processes and their characteristics in physical chemistry
  • Explore the implications of specific heat capacities in different types of gases
  • Practice solving problems involving irreversible adiabatic expansions
USEFUL FOR

This discussion is beneficial for students of physical chemistry, particularly those studying thermodynamics, as well as educators and professionals seeking to deepen their understanding of gas behavior during adiabatic processes.

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Homework Statement


Consider the adiabatic expansion of .553mol of an ideal monatomic gas with CV,m = 3R/2. The initial state is described by P = 6.25bar and T = 306K. Calculate the final temperature if the same gas undergoes an adiabatic expansion against an external pressure of P = 1.25bar to a final pressure P = 1.25bar.


Homework Equations


CVΔT = -PextΔV


The Attempt at a Solution


I need to find ΔT. P, V, and T are all variables, though, so I can't find ΔT because I don't know ΔV. What do I do?
 
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Use the ideal gas law to express the final volume algebraically in terms of the final temperature. Substitute this into your equation. The final temperature will be on both sides of the resulting equation. Collect terms involving the final temperature, and solve for it.
 
A little bit of annoying algebra, but I got it. Thank you very much.
 

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