Entropy Changes for Phase Changes

[Rita Chen 1B]

In Dr. Lavelle's lecture, he stated that phase changes have entropy changes. Can someone explain why?

[Naji Sarsam 1F]

A phase change affects the entropy of a molecule because intermolecular bonds are either being broken or formed, which affect how ordered the system is. In cases where intermolecular bonds are being broken--melting and boiling--the entropy increases as atoms are freer to move and occupy more energy states. in cases where intermolecular bonds are being formed--freezing and condensation--the entropy decreases as atoms are less free to move and occupy less energy states.