Heat not being a state property..

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Abigail Urbina 1K
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Joined: Thu Jul 27, 2017 3:01 am

Heat not being a state property..

Postby Abigail Urbina 1K » Sat Jan 20, 2018 7:02 pm

We know that the change in enthalpy is equal to qp, and we also know that enthalpy is a state property. However, we were taught in lecture that heat, which is q,is not a state property because it depends on the path it was taken to get to its final state. How is it not a state property when the change in enthalpy, which IS a state property is equal to qp?

Ridhi Ravichandran 1E
Posts: 35
Joined: Sat Jul 22, 2017 3:01 am

Re: Heat not being a state property..

Postby Ridhi Ravichandran 1E » Sat Jan 20, 2018 7:17 pm

Heat is not a state property because it is defined as the energy transferred to/from an object due to a temperature change. This can be accomplished in different ways (such as mixing vigorously or actually heating the object through an external source), so the path matters. Thus, it is not a state function.

It is the CHANGE in enthalpy that is a state function. Because we are only looking at the change, we only need to look at the initial and final states. How these states were reached is irrelevant.

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