The first law of thermodynamics is a formulation of the law of conservation of energy in the context of thermodynamic processes. The law distinguishes two principal forms of energy transfer, heat and thermodynamic work, … See more

The revised statement of the first law postulates that a change in the internal energy of a system due to any arbitrary process, that takes the system from a given initial thermodynamic state to a given final equilibrium thermodynamic state, can be … See more

The law is of great importance and generality and is consequently thought of from several points of view. Most careful textbook … See more

When the heat and work transfers in the equations above are infinitesimal in magnitude, they are often denoted by δ, rather than See more

The first law of thermodynamics is often formulated as the sum of contributions to the internal energy ($${\displaystyle U}$$) from all work ( See more

Cyclic processes
The first law of thermodynamics for a closed system was expressed in two ways by Clausius. One … See more

The first law of thermodynamics for closed systems was originally induced from empirically observed evidence, including calorimetric evidence. It is nowadays, however, taken to … See more