Thermodynamics 2

Microscopic and macroscopic descriptions of a system in equilibrium


Two-phase pure body in equilibrium. Phase diagram (P, T ). Case of liquid-vapor equilibrium: Clapeyron diagram (P, v), vapor titer.


Liquid-vapor equilibrium of water in the presence of an inert atmosphere.




First principle. Energy balances


Enthalpy associated with a phase transition: enthalpy of fusion, enthalpy of vaporization, enthalpy of sublimation.




Second principle. Entropy balances


Second principle: entropy state function, entropy created, entropy exchanged.


Laplace's law


Special case of a phase transition.




Thermal machines Application of the first and second principles to dithermic cyclic thermal machines: efficiency, Carnot's theorem.