Reversible vs. Irreversible reactions

isochoric/isometric: $\Delta V = 0$
isothermal: $\Delta T = 0$
isobaric: $\Delta P = 0$

Goyama_2A
Posts: 107
Joined: Sat Aug 24, 2019 12:17 am

Reversible vs. Irreversible reactions

I know that work is different for reversible and irreversible reactions, so how does my calculation of work differ for a reversible vs. an irreversible reaction? Additionally, what other values/calculations differ for reversible vs. irreversible reactions and how do I accommodate those differences (i.e. what different equations are used)?

Brian Tangsombatvisit 1C
Posts: 119
Joined: Sat Aug 17, 2019 12:15 am

Re: Reversible vs. Irreversible reactions

Reversible work = integral of Pdv, which simplifies to -nRTln(v2/v1). External pressure is not constant. During reversible processes, the system is always at equilibrium and therefore the entropy for these systems is 0. These processes are usually isothermal, meaning that energy lost by the system through work is slowly replenished by heat of the surroundings.

Irreversible work = -PdeltaV, where P is the constant external pressure. These processes are spontaneous, and therefore have a -G and S(univ) > 0. Temperature of the system would not be isothermal in this case.

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