Science - 2018-19

CH.5 c, g - Colligative Properties

The student will investigate and understand that the phases of matter are explained by kinetic theory and forces of attraction between particles. Key concepts include:
c) vapor pressure;
g) colligative properties.

Bloom's Levels:  Analyze; Understand

Adopted: 2010

BIG IDEAS

  • Colligative properties are affected by the addition or removal of a solute.

  • I can explain why nail polish remover evaporates faster than water.
  • I can choose what kind of ice melt to put on the walkways when it snows.

UNDERSTANDING THE STANDARD

  • Vapor pressure is the pressure of the vapor found directly above a liquid in a closed container. When the vapor pressuer equals the atmospheric pressre, a liquid boils. Volatile liquids have high vapor pressures, weak intermolecular forces, and low boiling points. Nonvolatile liquids have low vapor pressures, stronger intermolecular forces, and high boiling points.
  • Solutions can be a variety of solute/solvent combinations: gas/gas, gas/liquid, liquid/liquid, solid/liquid, gas/solid, liquid/solid, or solid/solid.
  • Polar substances dissolve ionic or polar substances; nonpolar substances dissolve nonpolar substances. The numer of solute particles changes the freezing point and boiling point of a pure substance.
  • A liquid's boiling point and freezing point are affected by changes in atmospheric pressure. A liquid's boiling point and freezing point are affected by the presence of certain solutes.

ESSENTIALS

In order to meet this standard, it is expected that students will

c)  interpret vapor pressure graphs.

g)  examine the polarity of various solutes and solvents in solution formation.


KEY VOCABULARY

boiling point elevation, colligative property, colloid, concentration, freezing point depression, heat of solution, Henry's law, immiscible, insoluble, miscible, molarity, mole fraction, osmosis, osmotic pressure, saturated solution, solubility, soluble, solvation, supersaturated solution, suspension, Tyndall effect, unsaturated solution, vapor pressure lowering


Updated: Nov 19, 2017