You're right, if the system is in equilibrium, the concentration is not changing. But that doesn't stop us from asking the hypothetical question: *if* some A transferred from one phase to another, what *would* be the change in the Gibbs energy? Here's an analogy: suppose you have some f(x), and I tell you that the slope df/dx is 0 at the minimum of the function. This is true, even though there is only one point at the minimum, and when you're at the minimum x can't be changing (so dx must be 0).
We have made the assumption that everything is happening at constant T and P. So, as the molecules of A change phase, some heat is transferred to/from the surroundings to maintain equilibrium with the external T, and the volume of the container increases/decreases to maintain equilibrium with the external P
Great explanation, sir! It was brief and clear. Thank you 😁
Thanks!
Hi, at around 8:06, why is dP = 0? Because from PV = nRT, dn might provoke a change in P.
Yes, it might, but we are considering conditions where T and P are held constant. This was specified (somewhat belatedly) @5:00 in the video
Sir I have a doubt: If component A is in equilibrium across 2 phases then shouldn't the no. of moles of A in both phases remain constant and dn(A)=0?
You're right, if the system is in equilibrium, the concentration is not changing.
But that doesn't stop us from asking the hypothetical question: *if* some A transferred from one phase to another, what *would* be the change in the Gibbs energy?
Here's an analogy: suppose you have some f(x), and I tell you that the slope df/dx is 0 at the minimum of the function. This is true, even though there is only one point at the minimum, and when you're at the minimum x can't be changing (so dx must be 0).
@@PhysicalChemistry Understood Sir✌
When some moles of compound A of phase β move down to phase α why doesn't the pressure and temperature of each phase change?
We have made the assumption that everything is happening at constant T and P. So, as the molecules of A change phase, some heat is transferred to/from the surroundings to maintain equilibrium with the external T, and the volume of the container increases/decreases to maintain equilibrium with the external P
@@PhysicalChemistry Thank you so much for taking the time to reply. I can understand now.🙂
Thank you very much for this helpful and clear video 💕
My pleasure!