Thermodynamic Relations, What are?

Welcome back MechanicalEI, Did you know that there exists a mnemonic diagram designed by Max Born just to remember some thermodynamic relations? This makes us wonder, What are thermodynamic relations? Before we jump in check out the previous part of this series to learn about the applications of entropy. Now, Thermodynamic relations refer to the famous maxwell relations which apply for a pure substance undergoing an infinitesimal reversible process defined by four equations.These equations apply to the four thermodynamic properties and are exact differentials of the type dz equals M dx plus N dy which can be expressed as dou M upon dou y with x constant equals dou N upon dou x with y constant. Using this method on the four equations we get the maxwell equations. During phase transactions like melting, vaporisation, sublimation the temperature and pressure remain constant while the entropy and volume change. The Clausius-Clapeyron relation helps in differentiating a discontinuous phase transition between two phases of matter denoted by a coexistence curve on a pressure temperature diagram. It does so by giving the relation between the slope of the tangents to this coexistence curve. There is a temperature change of in a real gas or liquid when it is forced through a valve or a porous plug while being kept insulated so that no heat is exchanged with the environment. This effect is called the Joule-Thompson effect and is widely exploited in thermal machines such as generators, heat pumps and Air conditioners. Hence, we learned about what the thermodynamic relations are then moved on to the Clausius Clapeyron and finally saw what the joule Thompson effect is.

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