Term: entropy, \(S\)
https://doi.org/10.1351/goldbook.E02149

Definition:
Quantity the change in which is equal to the heat brought to the system in a reversible process at constant temperature divided by that temperature. Entropy is zero for an ideally ordered crystal at 0 K. In statistical thermodynamics \[S=k\ \ln W\] where k is the Boltzmann constant and W the number of possible arrangements of the system.

Related Terms:
1) boltzmann constant (http://doi.org/10.1351/goldbook.B00695).

Source: Green Book, 2nd ed., p. 48 (https://goldbook.iupac.org/files/pdf/green_book_2ed.pdf)

Citation: 'entropy, \(S\)' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.E02149

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