Internal Energy and Formulation of the First Law
In thermodynamics, energy is used to describe and predict the behavior of physical systems. The internal energy (U) of a system is the sum of all microscopic forms of energy within the system, including molecular kinetic and potential energies, as well as contributions from electronic and nuclear energy levels. Although the individual components of internal energy cannot be measured directly, the internal energy of any system is well defined within thermodynamic theory.The first law of...