change in enthalpy

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Ekayana Sethi 2K
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change in enthalpy

Postby Ekayana Sethi 2K » Thu Jan 25, 2018 7:36 pm

is delta(H)=delta(U)-delta(n)*R*T or delta(H)=delta(U)+delta(n)*R*T? Also is work -P*delta(V) or +P*delta(V)?

Ashley Davis 1I
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Joined: Fri Sep 29, 2017 7:04 am

Re: change in enthalpy

Postby Ashley Davis 1I » Thu Jan 25, 2018 7:57 pm

for the second part of your question, i believe w = -PΔV when work is done BY the system and w = +PΔV when work is done ON the system.

AtreyiMitra2L
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Re: change in enthalpy

Postby AtreyiMitra2L » Thu Jan 25, 2018 8:00 pm

I believe it is deltaU = deltaH - delta(n)RT. This goes off of the concept that delta u is equal to q + w. (AKA the second one). Work is the second one. This occurs because of the idea of what the work is being done on or by what. In expansion, the work is being done ON the surroundings BY the system. Therefore, it is negative.


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