State function

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chemstudent_1K
Posts: 26
Joined: Fri Sep 25, 2015 3:00 am

State function

Postby chemstudent_1K » Fri Jan 15, 2016 3:44 pm

Why does heat need to be under constant pressure in order to be a state function? Conceptually, why is heat not a state function?

Jasmine Lam 1I
Posts: 20
Joined: Fri Sep 25, 2015 3:00 am

Re: State function

Postby Jasmine Lam 1I » Fri Jan 15, 2016 4:01 pm

Heat is not a state function because it depends on the pressure during heating/cooling and not just the initial and final temperatures and pressure, while enthalpy is measured at constant pressure. State functions are step independent functions and only the initial and the final values matter, not the steps.
Hope that helps

Ronald Yang 2F
Posts: 86
Joined: Fri Sep 25, 2015 3:00 am

Re: State function

Postby Ronald Yang 2F » Fri Jan 15, 2016 9:41 pm

Also want to add that heat at constant pressure is not a state function just because it is equal to ΔH, which is a state function. Heat, under any condition, is a path function.


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