- #1
Avatrin
- 245
- 6
Hi
The thing I am struggling with is why for reversible or quasistatic (depending on what book you use):
Q = TdS and W = -PdV
Thus, dU = TdS - PdV
What about reversible/quasistatic processes makes -PdV the only work the system can do?
While I know [itex] \frac{1}{T} = (\frac{dS}{dU})_{N,V}[/itex], I don't understand why Q = TdS in quasistatic/reversible processes. I also understand that [itex] dS = \frac{Q}{T} [/itex] was the original definition of entropy, but how am I supposed to understand this in terms of quasistatic processes?
What makes quasistatic/reversible processes so fundamentally different than other types of processes? I understand that they are always in equilibrium, but I cannot connect the dots.
The thing I am struggling with is why for reversible or quasistatic (depending on what book you use):
Q = TdS and W = -PdV
Thus, dU = TdS - PdV
What about reversible/quasistatic processes makes -PdV the only work the system can do?
While I know [itex] \frac{1}{T} = (\frac{dS}{dU})_{N,V}[/itex], I don't understand why Q = TdS in quasistatic/reversible processes. I also understand that [itex] dS = \frac{Q}{T} [/itex] was the original definition of entropy, but how am I supposed to understand this in terms of quasistatic processes?
What makes quasistatic/reversible processes so fundamentally different than other types of processes? I understand that they are always in equilibrium, but I cannot connect the dots.