Calculate the work done in polyatomic gas

AI Thread Summary
The discussion focuses on calculating the work done during an irreversible adiabatic expansion of a polyatomic gas. The initial parameters include 2 moles of gas at 300K and 10 atm, expanding to 1 atm. The work done is expressed as W = nCvΔT, with Cv derived from the universal gas constant and the specific heat ratio (γ). Participants highlight the challenge of determining the final temperature and volume, suggesting the use of the relationship PV^γ = constant, although there is a debate about its applicability to irreversible processes. The conversation emphasizes the need for alternative methods to find the necessary parameters for calculating work in this context.
paragchitnis
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Homework Statement


Calculate the work done by the system in an irreversible (single step) adiabatic expansion of 2 moles of a polyatomic gas (\gamma = 4/3) from 300K and pressure 10 atm to 1 atm.


Homework Equations


Work done in adiabatic process
W = nCv\DeltaT
n = Moles of gas
Cv = R/(\gamma-1) R-Universal gas constant
\DeltaT- Change in absolute temperature

The Attempt at a Solution


The given answer is 405R. I am unable to find out the change in temperature as final temperature and volume are unknown. Is there any other formula to calculate the work done in adiabatic expansion?
 
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Are you aware that P V^{\gamma} = constant for adiabatic processes? You can find the final temperature using this fact and the ideal gas equation of state.
 
Pi-Bond said:
Are you aware that P V^{\gamma} = constant for adiabatic processes? You can find the final temperature using this fact and the ideal gas equation of state.

I think PV\gamma= constant is applicable for adiabatic reversible processes only. It is irreversible process..
 

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