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 … See more

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

The first law of thermodynamics for closed systems was originally induced from empirically observed evidence, including calorimetric … See more

The first law of thermodynamics is often formulated as the sum of contributions to the internal energy ($${\displaystyle U}$$) from all work ($${\displaystyle W}$$), done on or by the system, and the amount of heat ($${\displaystyle Q}$$) supplied or withdrawn from the … See more

Cyclic processes
The first law of thermodynamics for a closed system was expressed in two ways by Clausius. One way referred to cyclic processes and the … 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