How to distinguish heat from work in irreversible processes?

Abstract

Abstract The theoretical foundations of the reservoir concept are presented and then applied to the discussion of two irreversible processes. As an alternative to what is stated in the literature, it is shown that heat and work can be clearly distinguished in irreversible processes, provided that the reservoir concept is considered. This discussion, which is expected to be both theoretically and instructively relevant, is intended primarily for graduate students and teachers, although it may also be of interest to undergraduate students with a solid background in thermodynamics. By covering specific examples of irreversible processes in which heat and work turn out to be controversial concepts, this article will also be useful in the introductory or upper-level undergraduate curriculum.