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The third law of thermodynamics (hereinafter "Third Law") states that "as a system approaches the zero absolute temperature (hereinafter "ZAT"), all processes cease and the entropy of the system approaches a minimum value. That minimum value is zero in the case of a perfect crystalline substance. Succinct statements of the Third Law include: The laws of thermodynamics in principle describe the specifics for the transport of heat and work in thermodynamic processes. ...
The zeroth law of thermodynamics may be succintly stated as: If two thermodynamic systems A and B are in thermal equilibrium, and B and C are also in thermal equilibrium, then A and C are in thermal equilibrium. ...
The first law of thermodynamics, a generalized expression of the law of the conservation of energy, states: the increase in the internal energy of a system is equal to the amount of energy added to the system by heating, plus the amount added in the form of work done on...
The second law of thermodynamics (Second Law hereinafter) states that the entropy of any totally isolated system not at thermal equilibrium will tend to increase over time, approaching a maximum value. ...
Thermodynamics (from the Greek thermos meaning heat and dynamis meaning power) is a branch of physics that studies the effects of changes in temperature, pressure, and volume on physical systems at the macroscopic scale by analyzing the collective motion of their particles using statistics. ...
Absolute zero is a fundamental lower bound on the temperature of any macroscopic system. ...
Ice melting - a classic example of entropy increasing In thermodynamics, thermodynamic entropy (or simply entropy) S is an important state function of a thermodynamic system: that is, a property depending only on the current state of the system, independent of how that state came to be achieved. ...
- All the temperature of a system approaches ZAT, all processes cease;
- As temperature goes to ZAT, the entropy of a system approaches a constant.
Absolute zero is a fundamental lower bound on the temperature of any macroscopic system. ...
Description
The Third Law states that the entropy of a system at ZAT is a well-defined constant. This is because a system at ZAT exists in its ground state, so that its entropy is determined only by the degeneracy of the ground state; or, it states that "it is impossible to reduce any system to ZAT in a finite number of operations, no matter how idealised." For other uses of the term entropy, see Entropy (disambiguation) The thermodynamic entropy S, often simply called the entropy in the context of thermodynamics, is a measure of the amount of energy in a physical system that cannot be used to do work. ...
Absolute zero is a fundamental lower bound on the temperature of any macroscopic system. ...
In physics, the ground state of a quantum mechanical system is its lowest-energy state. ...
The word degeneracy has more than one meaning: In general, degeneracy means reverting to an earlier, simpler, state In mathematics, a limiting case in which a class of object changes its nature so as to belong to another, usually simpler, class. ...
In simple terms, the Third Law states that the entropy of a pure substance at ZAT is zero. This Law establishes an absolute reference point for the calculation of entropy. The entropy relative to this reference point is the absolute entropy.
A special case is systems with a unique ground state, such as crystal lattices. The entropy of a perfect crystal lattice as defined by Nernst's theorem is zero (since ln1 = 0). However this disregards the fact that real crystals must be grown at finite temperature and possess an equilibrium defect concentration. When cooled down, they are generally unable to achieve complete perfection. This, of course, is in line with the observation that entropy must always increase, since no real process is reversible. In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal. ...
Another application of the Third Law concerns the magnetic moments of a material. Paramagnetic materials (moments random) will "order" as the temperature approaches ZAT. They may order in a ferromagnetic sense (all moments parallel to each other) or they may order in an antiferromagnetic manner.
Yet another application of the Third Law is the fact that at ZAT, no solid solutions should exist. Phases in equilibrium at ZAT should either be pure elements or atomically ordered phases. See J.P. Abriata and D.E. Laughlin, 2004, "The Third Law of Thermodynamics and low temperature phase stability," Progress in Materials Science 49: 367-387.
The Third Law was developed by Walther Nernst, during the years 1906-1912, and is thus sometimes referred to as Nernst's theorem. Walther Nernst. ...
See also In thermodynamics, an adiabatic process is a process in which no heat is transferred to or from working fluid. ...
In physics, the ground state of a quantum mechanical system is its lowest-energy state. ...
The laws of thermodynamics in principle describe the specifics for the transport of heat and work in thermodynamic processes. ...
For other uses of the term entropy, see Entropy (disambiguation) The thermodynamic entropy S, often simply called the entropy in the context of thermodynamics, is a measure of the amount of energy in a physical system that cannot be used to do work. ...
Thermodynamics (from the Greek thermos meaning heat and dynamis meaning power) is a branch of physics that studies the effects of changes in temperature, pressure, and volume on physical systems at the macroscopic scale by analyzing the collective motion of their particles using statistics. ...
A timeline of events related to thermodynamics, statistical mechanics, and random processes. ...
Further reading - Goldstein, Martin, and Inge F., 1993. The Refrigerator and the Universe. Harvard Univ. Press. Chpt. 14 discusses the Third Law. Overall, a gentle introduction to thermodynamics.
External links - 20+ Variations of the 3rd Law
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