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However, today the classical equation of entropy, = can be explained, part by part, in modern terms describing how molecules are responsible for what is happening: Δ S {\displaystyle \Delta S} is the change in entropy of a system (some physical substance of interest) after some motional energy ("heat") has been transferred to it by fast-moving ...
Figure 1. A thermodynamic model system. Differences in pressure, density, and temperature of a thermodynamic system tend to equalize over time. For example, in a room containing a glass of melting ice, the difference in temperature between the warm room and the cold glass of ice and water is equalized by energy flowing as heat from the room to the cooler ice and water mixture.
In more detail, Clausius explained his choice of "entropy" as a name as follows: [10] I prefer going to the ancient languages for the names of important scientific quantities, so that they may mean the same thing in all living tongues. I propose, therefore, to call S the entropy of a body, after the Greek
The maximum entropy principle: For a closed system with fixed internal energy (i.e. an isolated system), the entropy is maximized at equilibrium. The minimum energy principle: For a closed system with fixed entropy, the total energy is minimized at equilibrium.
The additional free volume causes an increase in the entropy of the polymers, and drives them to form locally dense-packed aggregates. A similar effect occurs in sufficiently dense colloidal systems without polymers, where osmotic pressure also drives the local dense packing [ 17 ] of colloids into a diverse array of structures [ 18 ] that can ...
Whether carried out reversible or irreversibly, the net entropy change of the system is zero, as entropy is a state function. During a closed cycle, the system returns to its original thermodynamic state of temperature and pressure. Process quantities (or path quantities), such as heat and work are process dependent.
However, after sufficient time has passed, the system reaches a uniform color, a state much easier to describe and explain. Boltzmann formulated a simple relationship between entropy and the number of possible microstates of a system, which is denoted by the symbol Ω. The entropy S is proportional to the natural logarithm of this number:
In statistical mechanics, free entropies frequently appear as the logarithm of a partition function. The Onsager reciprocal relations in particular, are developed in terms of entropic potentials. In mathematics , free entropy means something quite different: it is a generalization of entropy defined in the subject of free probability .