Coligative Properties Flashcards (Notes 23-35)

Vocabulary flashcards covering core concepts of boiling/freezing point changes, osmotic properties, vapor pressure, and electrolytes from the notes.

Boiling Point Elevation

Increase in the boiling point of a solvent when a nonvolatile solute is dissolved; ΔTb = Kb · m, where m is molality and Kb is the solvent’s ebullioscopic constant.

Freezing Point Depression

Decrease in the freezing point of a solvent when a nonvolatile solute is dissolved; ΔTf = Kf · m, where m is molality and Kf is the freezing point depression constant.

Molality (m)

Molars of solute per kilogram of solvent.

Kb (Boiling Point Elevation Constant)

Solvent-specific constant used in the boiling point elevation equation ΔTb = Kb · m.

Kf (Freezing Point Depression Constant)

Solvent-specific constant used in the freezing point depression equation ΔTf = Kf · m.

Osmosis

Flow of solvent through a semipermeable membrane from region of lower solute concentration to higher solute concentration.

Osmotic Pressure

Pressure required to stop osmosis; for dilute solutions, ∏ = M R T.

Osmotic Pressure Equation

∏ = M R T, where M = molarity, R = 0.08206 atm·L·mol⁻¹·K⁻¹, T = temperature in Kelvin.

Vapor Pressure Lowering (Raoult’s Law)

Dissolved solute lowers the solvent’s vapor pressure; Psolution ≈ Xsolvent · P°_solvent for ideal solutions.

Van’t Hoff Factor (i)

Number of particles in solution per formula unit of solute; accounts for electrolyte dissociation in colligative properties.

Electrolyte

Substance that dissociates into ions in solution, affecting colligative properties via the factor i.

Strong Electrolyte

Fully dissociates in water into ions.

Weak Electrolyte

Incompletely dissociates in water.

Non-Electrolyte

Does not dissociate in water; behaves as one particle per formula unit (i ≈ 1).

Section 13.5 Colligative Properties of Electrolytes

Relates vapor pressure, boiling point, freezing point, and osmotic pressure to the amount of dissolved electrolyte solute.