Why is the entropy change of water when it freezes expected to be negative?

Answer 1

Because heat is REMOVED during freezing, so the change in heat content is negative. Entropy tracks with heat content during an isothermal phase change via ds=dq/T.

Answer 2

Entropy is loosely explained as being a measure of the disorder in a system. In terms of atomic structure a solid is a more ordered state, where there are rigid crytalline structures holding molecules in fixed positions. On the other hand in a liquid state all the molecules are loose and moving around each other. (a gaseous state is more disordered again).

The higher the entropy of a system the MORE disordered it is. If you are increasing the order in a system entropy will decrease. So, freezing anything is making its molecular structure more ordered and is therefore decreasing entropy.

Answer 3

Water has a set heat capiity (sp) for every K you need I think 4.2 jolues of energy to raise it be 1 K.

But then melting ice into water there is a barrier that needs extra energy this is extra enegry is called latent heat of melting. So then the resevre process happens water into ice, this extra heat is not needed and wherefor it is given out.

Answer 4

because water does not spontaneously freeze. But, this, of course, is temperature dependent.

Answer 5

Because water becomes less random when it freeses (ice is a crystal).