Question

Crystallization of sodium acetate occurs spontaneously from a supersaturated solution. What can you deduce about the signs of ΔS and ΔH for this process?

Answer 1

Answer:

ΔS < 0

ΔH < 0

Explanation:

Recall that the process is crystallization. Crystallization involves conversion of aqueous ions back to solid. This process decreases the entropy of the system hence ΔS is negative.

But remember that a process is only spontaneous when ΔG <0 (negative). From;

ΔG = ΔH - TΔS

If  ΔS is negative, then (-TΔS) must be positive since  ΔS is negative. The only way to make the process spontaneous is to make ΔH negative so that ΔG also becomes negative.