What equation to use when finding work

[705340227]

When do I use w= -P * delta V versus w = -nRTln(Vfinal/Vinitial)?

[gabbi_r2C]

We use the first equation (w=-PdeltaV) when pressure is constant; you can derive this from the integral equation Dr. Lavelle gave us in lecture. We use the second equation (w=-nRTln(Vf/Vi)) when pressure is not constant, as you cannot pull out P from the integral equation nor can you solve the expression without substituting something for pressure, and the above equation is that derived substitution.

[SophiaNguyen_2L]

I believe you'd use W = - P x ∆V for irreversible expansions (pressure is constant). And on the other hand, you'd use W = -nRT ln (V2/V1) for reversible expansions (pressure is not constant).