Question

A substance has heat transfer out. Can you say anything about changes in s if the process is reversible? If it is irreversible?  

Answer 1

Reversible:  ds = dq/T < 0 since dq < 0

Irreversible: ds = dq/T + ds_gen = ? dq < 0 but ds_gen > 0 

You cannot say, ds depends on the magnitude of dq/T versus ds_gen