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Irreversible System

Posted: Fri Mar 13, 2020 5:29 pm
by eduardomorales5
How would we find the change in entropy for an irreversible system? Why would the entropy of the surroundings equal 0?

Re: Irreversible System

Posted: Fri Mar 13, 2020 5:58 pm
by Kishan Shah 2G
The questions would have to say isothermal irreversible, so you would use the deltaS=nRln(V2/V1) formula. The delta S obtained is the delta S of the system. For a irreversible system, the graph is a sharp vertical dip, which means the surroundings do not have time to react to this change, so the deltaS surroundings is 0, and deltaS univerise is equal to deltaS system.

Re: Irreversible System

Posted: Fri Mar 13, 2020 6:04 pm
by jisulee1C
Isothermal means a constant temperature, so we can use the formula ΔS = nR ln(V2/V1).Since entropy is a state function, only the initial and final states matter, not the pathway taken to get there. In this case for irreversible free expansion, the expansion is very fast therefore the surroundings don't have time to react to the entropy change of the system and since there is no time to react, delta S of the surroundings is zero and delta S of the universe = delta S of the system.