Question

Under what conditions does dA ≤ 0 define the spontaneity of a process?

Answer 1

Answer:

We know that dA = dU −TdS

dA = Helmoltz free energy, dU = Internal energy, T= Temperature and dS = Entropy change

dA = - Ve The reaction is the spontaneous.

dA = 0 The reaction is in equilibrium

dA = +Ve The reaction is the Nonspontaneous.

The conditions for the spontaneous reactions:

1) If dU = -Ve and dS = +Ve Then dA becomes -Ve.

2) If dU = -Ve and dS = -Ve but TdS < dU Then dA becomes -Ve.

and

3) If dU = +Ve and dS = +Ve but TdS > dU Then dA becomes -Ve.