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### Reversible vs Irreversible

Posted: Wed Feb 12, 2020 9:10 am
Is the only time we need to differentiate between reversible and irreversible when calculating work with: eversible: - nRT ln (v1/v2) and -Pext ΔV and when calculating delta S?

### Re: Reversible vs Irreversible

Posted: Wed Feb 12, 2020 11:16 am
From what we learned, we only distinguished our calculation for reversible and irreversible to calculate work and the total change in entropy of the universe.

### Re: Reversible vs Irreversible

Posted: Wed Feb 12, 2020 11:42 am
Yes, those equations can be used to find the change in entropy but also keep in mind what reversible and irreversible reactions mean. A reversible reaction is one that has infinitesimal changes that can be reversible by addition or subtraction at any given point in time, whereas irreversible changes immediately and cannot be reverted to its original state. Reversible reactions are most commonly used in the context of isothermal reactions where delta U and delta H equal 0.

### Re: Reversible vs Irreversible

Posted: Wed Feb 12, 2020 1:33 pm
Correct, reversible is applied to the equation W = -pexdeltaV, when the change in p is constant. The other equation is used when the process is irreversible, and usually isothermal (deltaT = 0).

### Re: Reversible vs Irreversible

Posted: Sun Feb 16, 2020 8:59 pm
How can you tell a process is reversible or irreversible without having a visual/picture?

### Re: Reversible vs Irreversible

Posted: Sun Feb 16, 2020 11:13 pm
Irreversible processes are usually spontaneous and quick where as irreversible processes are slow and maintain equilibrium throughout the entirety of the process. However, I believe it will be clearly stated or inferred in any test.