Concept
Thermodynamique
Concepts associés (53)
Inexact differential
An inexact differential or imperfect differential is a differential whose integral is path dependent. It is most often used in thermodynamics to express changes in path dependent quantities such as heat and work, but is defined more generally within mathematics as a type of differential form. In contrast, an integral of an exact differential is always path independent since the integral acts to invert the differential operator. Consequently, a quantity with an inexact differential cannot be expressed as a function of only the variables within the differential.
Règle des phases
En physique, et particulièrement en thermodynamique chimique, la règle des phases (ou règle des phases de Gibbs, ou règle de Gibbs) donne le nombre maximum de paramètres intensifs qu'un opérateur peut fixer librement sans rompre l'équilibre d'un système thermodynamique. Ce nombre de paramètres indépendants est appelé variance. Les paramètres sont choisis le plus souvent parmi la pression, la température et les concentrations des diverses espèces chimiques dans les diverses phases présentes.
Mechanical equivalent of heat
In the history of science, the mechanical equivalent of heat states that motion and heat are mutually interchangeable and that in every case, a given amount of work would generate the same amount of heat, provided the work done is totally converted to heat energy. The mechanical equivalent of heat was a concept that had an important part in the development and acceptance of the conservation of energy and the establishment of the science of thermodynamics in the 19th century.