Aim: How can one interpret the heating curve for a substance? Essential Questions: Compare the intermolecular forces of attraction of a substance as a solid; liquid; and a gas. Relate phase change to potential energy and kinetic energy of particles. Why is heat of vaporization greater than heat of fusion? Challenge!

Aim: How can one interpret the heating curve for a substance? The energy required to completely separate the molecules, moving from liquid to gas, is much greater that if you were just to reduce their separation, solid to liquid. The extra energy required to cause a phase transition is actually potential energy. It is the energy required to overcome the bonds of nearest neighbors to the point that a phase transition can occur.

Aim: How can one interpret heating curve for a substance? Vocabulary: Heat of fusion- Heat of vaporization- Intermolecular forces of attraction-

Aim: How can one interpret the heating curve for a substance? Explain what changes there are in: the distance between molecules potential energy speed of particles kinetic energy During the following processes: when ice turns from a solid to a liquid (melts.) when heated water is only in the liquid phase. c) when heated water turns from a liquid to a gas (vaporization.)