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Chemistry Forums for Students => Physical Chemistry Forum => Topic started by: Jetsu on February 18, 2021, 08:37:41 PM

Title: Adiabatic isobaric free expansion
Post by: Jetsu on February 18, 2021, 08:37:41 PM

I just have a question to pounder
Why cant we have an "adiabatic isobaric free expansion". I mean what are the factors and points that we have to exaplain.
adiabatic = q=0   and isobaric means constant pressure while free expansion means work done is 0. How do i link them?
Thanks.

Title: Re: Adiabatic isobaric free expansion
Post by: mjc123 on February 19, 2021, 05:25:12 AM

They are incompatible.
At constant pressure, work = PΔV, so it's not free expansion.
At constant T, PV = constant, so to keep the pressure constant during expansion, T has to increase. Where does the heat and the work come from if it's adiabatic?

Title: Re: Adiabatic isobaric free expansion
Post by: Enthalpy on March 03, 2021, 05:59:59 AM

Is the chemical composition constant?

"Adiabatic isobaric free expansion" could be imagined when foaming a plastic maybe.