6.2 Test Review

Objective 2: Summarize the quantitative and qualitative effects of colligative properties on a solution when a solute is added.

  1. Make sure you can calculate a molar mass for any given molecule or ionic compound using the masses given for each element on the periodic table.
  2. Make sure you can convert the mass in grams of any given molecule or ionic compound to moles or moles of any given molecule or ionic compound to mass in grams.
  3. Review metric equivalents. The main conversions you will need to do to solve colligative property problems are grams to kilograms and kilograms to grams. At this point in your education, you should also be fluent with milliliters to liters and liters to milliliters.
  4. Become fluent with the equations for freezing point depression and boiling point elevation. These equations can be reviewed on pages 448 and 451 respectively. Make sure you understand the solution process and the steps necessary to derive a logical conclusion. Know the freezing point constant (-1.86 oC/m) and the boiling point constant (0.51oC/m) for water. Why do you have to multiply the constant by the molality to solve freezing point depression or boiling point elevation?
  5. What is molality and why do we have to use it to calculate changes in freezing point and boiling point.
  6. What is freezing point and boiling point? What significance does it have in our everyday lives? How is it relevant to salted winter roads or homemade ice cream? What about cooking pasta?
  7. What is a phase diagram? What are the two variables that influence phase change (temperature and pressure)?
  8. What is a heating curve? Why are there points on the heating curve that are flat? What are the variables on the curve (energy and temperature)?
  9. Do you generally have an understanding of colligative properties? Are very familiar with at least two colligative properties (freezing point and boiling point)? Can you solve freezing point and boiling point problems using single variable calculations? Can you evaluate whether or not your answer is logical? Do you understand the applications of your work?