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The primary objective of chemical thermodynamics is the establishment of a criterion for determination of the feasibility or spontaneity of a given transformation. [3] In this manner, chemical thermodynamics is typically used to predict the energy exchanges that occur in the following processes: Chemical reactions; Phase changes; The formation ...
In the various theoretical descriptions of thermodynamics these laws may be expressed in seemingly differing forms, but the most prominent formulations are the following. Zeroth law The zeroth law of thermodynamics states: If two systems are each in thermal equilibrium with a third, they are also in thermal equilibrium with each other.
Maxwell relations in thermodynamics are often used to derive thermodynamic relations. [2] The Clapeyron equation allows us to use pressure, temperature, and specific volume to determine an enthalpy change that is connected to a phase change. It is significant to any phase change process that happens at a constant pressure and temperature.
For quasi-static and reversible processes, the first law of thermodynamics is: d U = δ Q − δ W {\displaystyle dU=\delta Q-\delta W} where δQ is the heat supplied to the system and δW is the work done by the system.
The history of thermodynamics is fundamentally interwoven with the history of physics and the history of chemistry, and ultimately dates back to theories of heat in antiquity. The laws of thermodynamics are the result of progress made in this field over the nineteenth and early twentieth centuries.
In combination with entropy determinations, it is also used to predict whether a reaction is spontaneous or non-spontaneous, favorable or unfavorable. Endothermic reactions absorb heat, while exothermic reactions release heat. Thermochemistry coalesces the concepts of thermodynamics with the concept of energy in the form of chemical bonds.
The first law of thermodynamics is essentially a definition of heat, i.e. heat is the change in the internal energy of a system that is not caused by a change of the external parameters of the system. However, the second law of thermodynamics is not a defining relation for the entropy.
In practice, simple idealized thermodynamic cycles are usually made out of four thermodynamic processes. Any thermodynamic processes may be used. However, when idealized cycles are modeled, often processes where one state variable is kept constant, such as: adiabatic (constant heat) isothermal (constant temperature) isobaric (constant pressure)