Hi, I found a derivation for heat transfer in a constant pressure process. It goes as follows:
Q + W = u2 - u1
Q = u2 - u1 + p(v2 - v1)
Since h = u + pv, Then
Q = h2 - h1
The first equation states that the sum of heat and work done is equal to the change in internal energy, I can comprehend up to there. But in the next line the work done is taken to the other side of the equation; both mathematically and physically I cannot understand how the work done (p(v2 - v1)) is still positive.
Mathematically I would say that taking work to the opposite side would make work negative.
Physically I would think that the amount of heat supplied/given off would be equal to the difference of initial and final internal energy minus the work done.
Hope someone could clear this out for me. Thanks
Q + W = u2 - u1
Q = u2 - u1 + p(v2 - v1)
Since h = u + pv, Then
Q = h2 - h1
The first equation states that the sum of heat and work done is equal to the change in internal energy, I can comprehend up to there. But in the next line the work done is taken to the other side of the equation; both mathematically and physically I cannot understand how the work done (p(v2 - v1)) is still positive.
Mathematically I would say that taking work to the opposite side would make work negative.
Physically I would think that the amount of heat supplied/given off would be equal to the difference of initial and final internal energy minus the work done.
Hope someone could clear this out for me. Thanks
0 commentaires:
Enregistrer un commentaire