Calculate the work done in polyatomic gas

[paragchitnis]

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 = nC_v$\Delta$T
n = Moles of gas
C_v = R/($\gamma$-1) R-Universal gas constant
$\Delta$T- 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?

 

[Pi-Bond]

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.

 

[paragchitnis]

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..