Colligative Properties Flashcards

Flashcards for reviewing colligative properties, including freezing point depression, boiling point elevation, and Raoult's Law.

Colligative Properties

Properties of solutions that depend on the number of solute particles, not their identities.

Dissociation of Solutes

Solutes that dissociate produce more particles in solution than those that do not.

Van't Hoff factor (i)

The number of moles of dissolved particles produced from each mole of solute compound.

Effect of Increased Solute Particles

As the number of dissolved particles increases, freezing point and vapor pressure decreases, while boiling point and osmotic pressure increase.

Effect of Solute on Liquid Range

The presence of a solute expands the liquid range of the solvent.

Freezing Point Depression Equation

Tf = Tf° - ΔTf = Tf° - i * m * Kf, where Tf is the new freezing point, Tf° is the freezing point of the pure solvent, i is the van't Hoff factor, m is the molal concentration, and Kf is the freezing point depression constant.

Freezing Point Depression Change Equation

ΔTf = i * m * Kf, where ΔTf is the size of the change in freezing point, i is the van't Hoff factor, m is the molal concentration, and Kf is the freezing point depression constant.

Boiling Point Elevation Equation

Tb = Tb° + ΔTb = Tb° + i * m * Kb, where Tb is the new boiling point, Tb° is the boiling point of the pure solvent, i is the van't Hoff factor, m is the molal concentration, and Kb is the boiling point elevation constant.

Raoult's Law

The vapor pressure of a solution is equal to the mole fraction of the solvent times the vapor pressure of the pure solvent.

Raoult's Law Equation

Pi = xi * Pi°, where Pi is the vapor pressure of component i above the solution, xi is the mole fraction of i in the solution, and Pi° is the vapor pressure of pure component i under current conditions.

Volatile Compounds

Compounds with significant vapor pressures.

Nonvolatile Compounds

Compounds with negligible vapor pressures.