1451ch11

Key Topics:

I feel like the main idea of this chapter is to look at the properties of matter like phase, boiling point, vapor pressure, and to understand these on a molecular level. To do this, we will spend a lot of time talking about intermolecular forces. You should be able to use Intermolecular Forces to explain the properties and to understand differences between different molecules. For example, why does water have a much higher boiling point than other molecules of similar size?

Phases of Matter
- Be able to describe a solid, liquid, and gas in terms of the substance's molecules. For example, a gas has indefinite volume and shape because the molecules have enough kinetic energy to completely overcome the intermolecular forces making the molecules free-moving.
- Also note that the heat required for a phase change (solid to liquid or liquid to gas) increases the kinetic energy of the particles to a level that they can overcome the intermolecular forces that hold them together.
Intermolecular forces:
- You MUST be able to draw a Lewis Structure and VSEPR shape to be able to understand intermolecular forces! (See Chapters 9 and 10)
- You MUST be able to determine if the molecule you have drawn is polar! (See Chapter 10)
- At the heart of Intermolecular Forces is Coulomb's law (pg 459). You don't have to calculate a number, but you should know what Coulomb's law means, and what changing charge magnitudes and distance do to the attractive force between the molecules. Assuming we are dealing with charges of opposite sign:
  - Charges (q): Increase charges, increase the attractive forces
  - Distance (r): When the distance between two charges is increased, the attractive force becomes smaller.
- You should know the types of intermolecular forces, know the definitions and also how each force comes about, and know normal magnitude ranges for each force.
  - You should realize that everything (as in molecules and atoms) has dispersion forces, but we usually use a hierarchy and only talk about the dipole-dipole forces in a polar molecule because these are usually much larger (and more important). Take water for example, everyone talks about the hydrogen bonding done by this molecule and ignores that it also has dispersion forces because these are so small in comparison.
- Be able to look at two or more molecules and predict which has a higher/lower boiling/melting point based on the intermolecular forces present. To do this you should be able to rank the molecules in order of increasing or decreasing magnitudes of intermolecular forces.
- Ion-dipole forces: These are the forces that make it favorable for electrolytes to dissociate in solution. These forces are not present in pure substances!
Surface Tension/Viscosity/Capillary Action/Vapor Pressure

Have a working knowledge of each of these properties. Know the definitions
You should be able to discuss these in terms of Intermolecular Forces. Just like boiling point, you should be able to compare these properties between different molecules.
You should spend some time looking at the distribution of thermal energy. Know how the distribution changes with temperature, and what the vertical line means on the chart.

How does this line change for a molecule with larger/smaller Intermolecular Forces?

Be able to use the Clausius-Clapeyron equation.
Understand the processes of sublimation and fusion.
Heat of Fusion/vaporization/sublimation
- What does the number correspond to? Be able to write the reaction (process) associated with each of these heats.
Heating curve
- I expect you to be able to draw, explain, and calculate the heat released or absorbed by any temperature change process for ANY PURE SUBSTANCE! Water is the example in the book, but you should be prepared for other substances.
Phase diagrams
- Be able to label a phase diagram with the phase and important points.
- Be able to navigate a phase diagram. Use one to determine if a phase change occurred during a change in temperature or pressure.
- How can you tell if the slope of the solid/liquid boundary line is positive or negative.
Solids
- Be able to compare Melting points based on type of solid
- Know what a unit cell is, and how to count the atoms in it.
- What is the coordination number?