Chapter 10: States of Matter & Intermolecular Forces Notes

Phase Change Diagram

A phase change diagram typically shows the different states of matter: solid, liquid, and gas along with the phase transitions (melting, freezing, boiling, and condensing). In a typical diagram:

1. Solid: Represented on the left side at lower temperature.
2. Liquid: In the middle region, where temperature increases slightly.
3. Gas: Found on the right side at higher temperatures.

Transitions:

• Melting: Solid to liquid (enthalpy change positive, absorbing heat).
• Freezing: Liquid to solid (enthalpy change negative, releasing heat).
• Boiling: Liquid to gas (enthalpy change positive, absorbing heat).
• Condensation: Gas to liquid (enthalpy change negative, releasing heat).

States of Matter Graph Diagram

The states of matter can also be visually represented using graphs:

• Temperature vs. Time Graph for a substance being heated (Heating Curve):

  • Shows temperature increase with time and plateaus where phase changes occur.
  • Y-axis: Temperature (°C)
  • X-axis: Time (min)

• Pressure vs. Temperature Graph (Phase Diagram):

  • Indicates the state of a substance at various pressure and temperature points.
  • Shows regions of solid, liquid, gas, and points of phase equilibrium.