The thermodynamics is the discipline that within mother science, Physical, deals with study of the relationships established between heat and other forms of energy. Among other issues, thermodynamics deals with analyzing the effects produced by changes in magnitudes such as: temperature, density, pressure, mass, volume, in systems and at a macroscopic level.
The basis on which all studies of thermodynamics hang is the circulation of energy and how it is capable of infusing movement.
It is worth noting that it was precisely this question that promoted the development of this science, since its origin was due to the need to increase the efficiency of the first steam engines.
So, since this kickoff, thermodynamics has been concerned with describing how systems respond to changes that occur in their environment, and can be applied to an infinity of situations, both in science and engineering, such as : engines, chemical reactions, phase transitions, transport phenomena, black holes, among others. And therefore its results are really appreciated by chemistry, physics and chemical engineering.
Meanwhile, thermodynamics has three fundamental laws ...the first law It is popularly known as the principle of conservation of energy and holds that if one system exchanges heat with another, its own internal energy will change. In this case, heat will be the necessary energy that a system must exchange to compensate for the differences between internal energy and work.
On your side, the second law , proposes different restrictions for energy transfers, which could be specified if the first law is taken into account; The second principle speaks of the regulation of direction in which the thermodynamic processes are carried out, imposing the possibility that they develop in the opposite direction. This second law is supported by the entropy (physical quantity that measures part of the energy that can be used to produce work).
And the third and last law argues that it is impossible to reach a temperature that is equal to absolute zero through a finite number of physical processes.
And the most important processes that take place in thermodynamics are: isothermal (the temperature does not change), isobaric (the pressure does not change), isochors (the volume does not change) and adiabatic (no heat transfer occurs).