Hii have a few questions about entropy:why does the definition

[Gavroy]

hi

i have a few questions about entropy:

why does the definition of entropy stress the fact that the heat exchange by the system is reversible(dS=dQ_rev/T)?

am i right, that processes are only reversible iff ΔS=0 and therefore e.g. isothermic, isobaric and isochoric processes even of ideal gases are irreversible in general?

 

[Studiot]

I have placed an answer in your other thread, which is basically about the same thing so all the stuff is together in one place.

https://www.physicsforums.com/showthread.php?p=4005901#post4005901