Αποτελέσματα Αναζήτησης
13 Μαΐ 2023 · Changes in entropy (ΔS Δ S), together with changes in enthalpy (ΔH Δ H), enable us to predict in which direction a chemical or physical change will occur spontaneously. Before discussing how to do so, however, we must understand the difference between a reversible process and an irreversible one.
28 Απρ 2023 · We introduce heuristic arguments to infer that \ (\Delta S=0\) is not possible for a spontaneous process in an isolated system. From this, we show that \ (\Delta S_ {universe}>0\) for any spontaneous process and hence that \ (\Delta S_ {universe}=0\) is not possible for any spontaneous process.
Hence, the entropy change may be defined as the amount of the heat absorbed isothermally and reversibly divided by the temperature at which the heat is absorbed. Being a state function, the change in entropy always depends upon the initial and final state and not upon the path followed.
For reversible processes (the most efficient processes possible), the net change in entropy in the universe (system + surroundings) is zero. Phenomena that introduce irreversibility and inefficiency are: friction, heat transfer across finite temperature differences, free expansion, ...
Abstract: We introduce an entropy technique which allows to treat some infinite-dimenslonal extensions of the classical duality equations for the time reversal of diffusion processes. i. Introduction Consider the time reversal of a process X t (0~t~l) with stochas- tic differential equation
Rearranging terms yields \[\dfrac{Q_c}{T_c} = \dfrac{Q_h}{T_h}\] for any reversible process. \(Q_c\) and \(Q_h\) are absolute values of the heat transfer at temperatures \(T_c\) and \(T_h\), respectively. This ratio of \(Q/T\) is defined to be the change in entropy \(\Delta S\) for a reversible process, \[\Delta S = \left(\dfrac{Q}{T} \right ...
We introduce an axiomatic thermodynamic theory for the general diffusion process and prove a theorem concerning entropy and irreversibility: the equiva-lence among time-reversibility, zero entropy production, symmetricity of the stationary diffusion process, and a potential condition.
