Unit 5

There are two topics in Unit 5.

In the second unit of this course, we took a closer look at the gas phase.  This unit will begin with a closer look at the liquid and solid phases and the forces (intermolecular forces) that allow substances to exist as liquids and solids under the right conditions.

The unit (and course) will close with a more detailed look at properties, characteristics, and calculations of solutions (solutions were introduced in Unit 2.)

Unit 5 Learning Objectives

Intermolecular Forces, Liquids, and Solids

1. 1. Explain the origin of the various types of intermolecular forces and indicate the kinds of intermolecular forces expected for a substance given its molecular structure.
   2. Distinguish between intermolecular and intramolecular forces.
   3. Explain the terms viscosity, surface tension, capillary action, meniscus, adhesion and cohesion.
   4. List the different phase changes and identify them as endothermic or exothermic.
   5. Solve problems involving enthalpies of fusion and vaporization.
   6. Describe how the vapor pressure of a substance is effected by temperature and intermolecular forces of attraction.
   7. Define boiling point and normal boiling point and know the effect of pressure, intermolecular forces, and molar mass on each.
   8. Understand the factors that influence the rate of evaporation and the relationship between boiling and evaporation.
   9. Given the critical temperature and pressure of a substance, describe the conditions necessary to convert it from a gas to a liquid.
   10. Distinguish between crystalline and amorphous solids and give an example of each.
   11. Define unit cell and describe the number of atoms and their location in a simple cubic (primitive cubic), body-centered cubic and face-centered cubic unit cell.
   12. Use a phase diagram to determine the physical state of a substance.

Properties of Solutions

1. Explain the solution process (solvation).
2. Describe the energy changes that occur during the solvation and relate these to particle interactions.
3. Define the terms solubility, miscible, and immiscible.
4. Explain the effect of temperature and pressure on solubility.
5. Use the phrase “”like dissolves like”” to predict whether two substances will be soluble in each other.
6. Describe the effects of pressure and temperature on solubilities.
7. Solve problems involving mass percent, parts per million (ppm), parts per billion (ppb), mole fraction, molarity, and molality.
8. Given the solubility of a gas in a liquid at one pressure, determine its solubility at a different pressure using Henry’s Law.
9. Describe the colligative effects of solute particles on the vapor pressure, boiling point, freezing point and osmotic pressure of a solution.
10. Use Raoult’s Law to calculate a solution’s vapor pressure.
11. Calculate the boiling point and freezing point of a solution from colligative properties data.
12. Calculate molar masses and molarities from colligative properties data.
13. Define osmotic pressure and calculate osmotic pressure, molarity, or the Van’t Hoff factor given information about the solution.