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

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The discussion centers on the concept of entropy, particularly its definition emphasizing reversible heat exchange (dS=dQ_rev/T). It is clarified that processes are only reversible if the change in entropy (ΔS) equals zero, implying that isothermal, isobaric, and isochoric processes involving ideal gases are generally irreversible. The importance of reversible processes in thermodynamics is highlighted, as they maintain equilibrium and do not increase entropy. The conversation also references a related thread for further context on the topic. Understanding these principles is crucial for grasping the nature of thermodynamic processes.
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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?
 
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