Adiabatic Expansion of a Gas: Final Pressure-Volume Product Calculation

AI Thread Summary
The discussion focuses on calculating the final pressure-volume product for a diatomic gas undergoing adiabatic expansion. The initial conditions include a pressure of 365 Pa and a volume of 70 m³, with the gas doing 101 J of work. The user correctly identifies the degrees of freedom as 3, leading to a value of ϒ=1.4 for diatomic gases. Despite applying the adiabatic work equation, the user is uncertain about their calculations, questioning whether they are approaching the problem correctly or if the answer might be incorrect. The thread highlights the importance of understanding degrees of freedom in gas behavior during adiabatic processes.
vetgirl1990
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Homework Statement


A gas consisting of diatomic molecules that can rotate but not oscillate at a given range of temperatures expands adiabatically from pressure of 365Pa and volume of 70m3, doing 101J of work, while expanding to a final volume. What is its final PV (pressure volume) product?

Homework Equations


For an adiabatic expansion:
W = (1/ϒ-1)(pfvf - pivi)

The Attempt at a Solution


i) Degrees of freedom: 3
Therefore, ϒ=1.4

ii) Plug and chug of the equation above.
W = (1/ϒ-1)(pfvf - pivi)
101 = (1/1.4-1)(pfvf - 365*70)
101 = 2.5pfvf - 63875
pfvf = 25590 Pa / m3

I'm fairly certain I found the degrees of freedom correctly, and the latter part of my calculations is pretty straightforward... Still getting the wrong answer, however. Chance that the answer is wrong? Or am I approaching the problem incorrectly?
 
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Isn't it 3 degrees of freedom for a monatomic gas?
 

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