Leyes

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Thermodynamics
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Annotated color version of the original 1824Carnot heat engine showing the hot body (boiler), working body (system, steam), and cold body (water), the letters labeled according to the stopping points in Carnot cycle.
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Thermodynamics is a physical science that studies the effects on material bodies, and on radiation in regions of space, of transfer of heat and of work done on or by the bodies or radiation. It interrelates macroscopic variables,such as temperature, volume and pressure, which describe physical properties of material bodies and radiation, which in this science are called thermodynamic systems.
Historically, thermodynamics developed out of a desire to increase the efficiency of earlysteam engines, particularly through the work of French physicist Nicolas Léonard Sadi Carnot (1824) who believed that the efficiency of heatengines was the key that could help France win the Napoleonic Wars.[1] Scottish physicist Lord Kelvin was the first to formulate a concise definition of thermodynamics in 1854:[2]
Thermo-dynamics is the subject of the relation of heat to forces acting between contiguous parts of bodies, and the relation of heat to electrical agency.
Initially, the thermodynamics of heat engines concerned mainly thethermal properties of their 'working materials', such as steam. This concern was then linked to the study of energy transfers in chemical processes, for example to the investigation, published in 1840, of the heats of chemical reactions[3] by Germain Hess, which was not originally explicitly concerned with the relation between energy exchanges by heat and work. Chemical thermodynamics studies thethe role of entropy in chemical reactions.[4][5][6][7][8][9] [10][11][12]Also, statistical thermodynamics, or statistical mechanics, gave explanations of macroscopic thermodynamics by statistical predictions of the collective motion of particles based on the mechanics of their microscopic behavior.
Thermodynamics describes how systems change when they interact with one another or with theirsurroundings. This can be applied to a wide variety of topics in science and engineering, such asengines, phase transitions, chemical reactions, transport phenomena, and even black holes. The results of thermodynamics are essential for other fields of physics and for chemistry, chemical engineering, aerospace engineering, mechanical engineering, cell biology, biomedical engineering,materials science,and are useful for other fields such as economics.[13][14]
Many of the empirical facts of thermodynamics are comprehended in its four laws. The first law specifies that energy can be exchanged between physical systems as heat and thermodynamic work.[15] The second law concerns a quantity called entropy, that expresses limitations, arising from what is known as irreversibility, on the amount ofthermodynamic work that can be delivered to an external system by a thermodynamic process.[16] Many writers offer various axiomatic formulations of thermodynamics, as if it were a completed subject, but non-equilibrium processes continue to make difficulties for it.
Contents [hide] * 1 Introduction * 2 History * 2.1 Etymology * 3 Branches of description * 3.1 Classicalthermodynamics * 3.2 Statistical thermodynamics * 3.3 Chemical thermodynamics * 3.4 Treatment of equilibrium * 4 Laws of thermodynamics * 5 System models * 6 States and processes * 6.1 Thermodynamic state variables * 6.2 Thermodynamic processes * 6.2.1 Dependent and independent variables for a process * 6.2.2 Changes of state of a system * 6.2.3 Cyclic...