yes, I am not picking any state variable in the middle of the free expansion. what i want to do is comparing the state function H enthalpy at the start and the end of the free expansion.
apparently, the enthalpy change for a free expansion is zero.
However, by taking another reversible Path...
Hi Studiot,
Thanks for the discussion. To answer your quesion:
"why you think w = 0 for the adiabatic irreversible path"
my path B is a free expansion path. a free expansion path does zero work.
see Free_expansion in wikipedia.
And actually, I only try to specify two variables P and V...
Thanks for your reply
the V2 in path B is assumed equal to V2 in path A. therefore, Path B and Path A could both reach a same state, P2, V2, and T1.
the vacuum part is V2-V1, it's like lift a barrier and let the gas go to extra V2-V1 part and reach V2. I don't want V2 go infinite.
Consider gas here as idea gas.
The gas expands from state 1: P1, V1 and T1 to state 2: P2, V2, and T1 using two different paths:
Path A: reversible expansion at constant T
Path B: irreversible expansion by releasing the gas to a vacuum to achieve V2 at adiabatic condition.
Thing I...