Question

Predict whether the changes in enthalpy, entropy, and free energy will be positive or negative for the freezing of water, and explain your predictions. How does temperature affect the spontaneity of this process?

Answer 1

Ok so if you freezing water your going from lower order to a higher order arrangement. Think that molecules as liquids are more random in their movements and can freely flow and have a relatively high disorder. Remember that molecules as solids are rigidly held in place without the ability to freely flow and therefore have a lower disorder/ higher order. So the entropy will overall decrease.

So when your freezing water you must remove energy from the liquid molecules so that they are able to obtain a solid structure. If energy is being removed from the liquid molecules then that means that this process is exothermic and energy is released into the environment.

Now free energy is something that relates both entropy and enthalpy together in the form of this equation
\[\Delta G = \Delta H - T \Delta S\]
Think our entropy value was positive and our enthalpy value was negative. How would free energy relate?

Answer 2

Thank you so much for replying!! I'm honestly not sure.. I don't get this at all. ): @sweetburger