Enthalpy and state property

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AlyssaBei_1F
Posts: 99
Joined: Fri Sep 28, 2018 12:17 am

Enthalpy and state property

Postby AlyssaBei_1F » Mon Jan 28, 2019 9:56 am

Can someone explain how enthalpy is a state property?

mcredi
Posts: 63
Joined: Fri Sep 28, 2018 12:16 am

Re: Enthalpy and state property

Postby mcredi » Mon Jan 28, 2019 10:00 am

Enthalpy is a state function because it depends only on two thermodynamic properties of the state the substance is at the moment (like temperature and pressure, or temperature and entropy, or any pair of other state functions). It does not depend on the path followed by the substance to get there. Enthalpy change is NOT a state function because it is a difference between two values of a state function (depends on a total of 4 state variables: 2 marking the initial state and 2 more marking the final state)

Daisylookinland
Posts: 46
Joined: Fri Sep 28, 2018 12:28 am

Re: Enthalpy and state property

Postby Daisylookinland » Mon Jan 28, 2019 1:31 pm

Enthalpy is a state property because the value of enthalpy is determined by its current state, not on the pathway taken to obtain that value. To use Dr. Lavelle's example from class, if someone went on a hike, the distance they travelled would not be a state property, however, their altitude change would be.


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