Heat and state function

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Heat and state function

Postby ZoeHahn1J » Thu Jan 11, 2018 10:51 pm

Why is heat not a state function? The explanation in the textbook uses both heat and work to show how it is not, but I'm a little unclear on the concept of heat alone not being a state function. Thank you!

Angela G 2K
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Re: Heat and state function

Postby Angela G 2K » Thu Jan 11, 2018 10:59 pm

Heat is not a state function because of this equation: q + w = U, where U is the internal energy of the system, q is the heat, and w is the work. Work is not a state function since it depends on the distance an object is moved, or the path, and so therefore the heat must also depend on the path.

Brigitte Phung 1F
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Re: Heat and state function

Postby Brigitte Phung 1F » Fri Jan 12, 2018 12:48 am

Heat is path dependent and therefore cannot be determined simply by its current state. When calculating the values of both heat and work, it matters how the end condition is achieved. Therefore, you cannot simply subtract the final condition from the initial condition as you would for a state function. Hope this helps!

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