Comparison of Work and Heat

Similarities:

(i) Both are path functions and inexact differentials.

(ii) Both are boundary phenomenon i.e., both are recognized at the boundaries of the system as they cross them.

(iii) Both are associated with a process, not a state. Unlike properties, work or heat has no meaning at a state.

(iv) Systems possess energy, but not work or heat.

Dissimilarities:

(i) In heat transfer temperature difference is required.

(ii) In a stable system there cannot be work transfer, however, there is no restriction for the transfer of heat.

(iii) The sole effect external to the system could be reduced to rise of a weight but in the case of a heat transfer other effects are also observed.