Entropy (order and disorder)
Interpretation of entropy as the change in arrangement of a system's particles
In thermodynamics, entropy is often associated with the amount of order or disorder in a thermodynamic system. This stems from Rudolf Clausius' 1862 assertion that any thermodynamic process always "admits to being reduced [reduction] to the alteration in some way or another of the arrangement of the constituent parts of the working body" and that internal work associated with these alterations is quantified energetically by a measure of "entropy" change, according to the following differential expression: ∫ δ Q T ≥ 0 {\displaystyle \int \!{\frac {\delta Q}{T}}\geq 0} where Q = motional energy ("heat") that is transferred reversibly to the system from the surroundings and T = the absolute temperature at which the transfer occurs. In the years to follow, Ludwig Boltzmann translated these 'alterations of arrangement' into a probabilistic view of order and disorder in gas-phase molecular systems.
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