Generic Heating/Cooling Curve

• Freezing is the phase change as a substance changes from a liquid to a solid.
• Melting is the phase change as a substance changes from a solid to a liquid.
• Condensation is the phase change as a substance changes from a gas to a liquid.
• Vaporization is the phase change as a substance changes from a liquid to a gas.

Generic Phase Diagram

• Sublimation is the phase change as a substance changes from a solid to a gas without passing through the intermediate state of a liquid.
• Deposition is the phase change as a substance changes from a gas to a solid without passing through the intermediate state of a liquid.
• TRIPLE POINT - The temperature and pressure at which the solid, liquid, and gas phases exist simultaneously.
• CRITICAL POINT - The temperature above which a substance will always be a gas regardless of the pressure.
• NOTE:
  • The solid phase is more dense than the liquid phase.
  • The line between the solid and liquid phases is a curve of all the freezing/melting points of the substance.
  • The line between the liquid and gas phases is a curve of all the boiling points of the substance.
• Freezing Point - The temperature at which the solid and liquid phases of a substance are in equilibrium at atmospheric pressure.
• Boiling Point - The temperature at which the vapor pressure of a liquid is equal to the pressure on the liquid.
  • Normal (Standard) Boiling Point - The temperature at which the vapor pressure of a liquid is equal to standard pressure (1.00 atm = 760 mmHg = 760 torr = 101.325 kPa)

Phase Diagram for Water

• For water, the liquid phase is more dense than the solid phase due to hydrogen bonding.

Next:  "Acids and Bases:  Development of Acids and Bases"