Chapter 13: Physical Properties of Solutions (Vocabulary)

Vocabulary flashcards covering key terms from Chapter 13: Physical Properties of Solutions.

Solution

A homogeneous mixture of two or more substances; consists of a solvent and one or more solutes.

Solvent

The component of a solution present in the greatest amount that dissolves the solute.

Solute

Substance dissolved in a solvent.

Unsaturated solution

Contains less solute than the solvent’s capacity to dissolve at a given temperature.

Saturated solution

Contains the maximum amount of solute that will dissolve in the solvent at a given temperature.

Supersaturated solution

Generally unstable; contains more dissolved solute than would normally be possible under the given conditions.

Solvation

Interaction of a solvent with the dissolved solute; solute molecules are surrounded by solvent molecules.

Solute–solute interactions

Intermolecular forces between solute particles that must be overcome during dissolution.

Solvent–solvent interactions

Intermolecular forces between solvent molecules that must be overcome to create space for the solute.

Solute–solvent interactions

Interactions between solute and solvent that promote dissolution.

ΔHsoln

Overall enthalpy change of solution: ΔHsoln = ΔH1 + ΔH2 + ΔH3; ΔH3 is exothermic (negative).

Like dissolves like

Solubility depends on similarity of intermolecular forces; polar solutes dissolve in polar solvents, nonpolar in nonpolar.

Miscible

Two liquids that are completely soluble in each other in all proportions.

Immiscible

Liquids that do not form a homogeneous solution when mixed.

Henry’s law

Solubility of a gas in a liquid is proportional to its partial pressure: c = kP.

Dalton’s law

Total pressure of a gas mixture equals the sum of the partial pressures of its components.

Molarity

Moles of solute per liter of solution.

Molality

Moles of solute per kilogram of solvent.

Mole fraction

Moles of a component divided by the sum of moles of all components.

Percent by mass

Mass of solute divided by the total mass of the solution, times 100%.

Concentration

The amount of solute relative to the volume of solution or to the amount of solvent.

Colligative properties

Properties that depend on the number of solute particles, not their identity (e.g., vapor-pressure lowering, boiling-point elevation, freezing-point depression, osmotic pressure).

Vapor-pressure lowering

Decrease in a solvent’s vapor pressure caused by the presence of a nonvolatile solute.

Boiling-point elevation

Increase in the boiling point of a solvent upon addition of a solute.

Freezing-point depression

Decrease in freezing point when a solute is dissolved.

Osmotic pressure

Pressure required to prevent osmosis; a colligative property.

Ionization

Breakup of the ionic lattice of a solid into ions in solution.

Hydration

Water molecules surround and stabilize released ions in solution.

Gibbs free energy of dissolution

Driving force for dissolution; ΔG = ΔHsoln − TΔSsoln; dissolution is favorable when ΔG < 0.