Solutions and Colligative Properties

Flashcards covering key vocabulary and concepts related to solutions, solubility, and colligative properties.

Solute

The gas (or solid) in a solution of gases (or solids), or the component present in the smaller amount.

Solvent

The liquid in the case of a solution of gases or solids, or the component present in the larger amount.

Miscible

Solutions that dissolve into each other.

Immiscible

Solutions that do not dissolve into each other.

Solubility

The amount of solute that dissolves in a given quantity of solvent at a given temperature.

Unsaturated Solution

A solution not in equilibrium with respect to a given dissolved substance and in which more of the substance can be dissolved.

Hydration

The attraction of ions for water molecules, favoring the dissolving of an ionic solid in water.

Ion-Dipole Force

Attractive force between a neutral molecule with a dipole and an ion (cation or anion).

Lattice Energy

The energy holding ions together in the crystal lattice; opposes dissolving.

Energy of Hydration

The energy associated with the attraction between ions and water molecules; favors dissolving.

Henry's Law

The solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the solution.

Colligative Properties

Properties of solutions that depend on the concentration of solute molecules or ions in solution but not on the chemical identity of the solute.

Molarity

Moles of solute per liter of solution (mol/L).

Mass Percentage of Solute

(Mass of solute / mass of solution) x 100%

Molality

Moles of solute per kilogram of solvent (mol/kg).

Mole Fraction

Moles of substance A / total moles of solution.

Vapor-Pressure Lowering

A colligative property equal to the vapor pressure of the pure solvent minus the vapor pressure of the solution.

Raoult's Law

The partial pressure of solvent over a solution equals the vapor pressure of the pure solvent times the mole fraction of solvent in the solution: PA = P°A * XA

Boiling-Point Elevation

A colligative property of a solution equal to the boiling point of the solution minus the boiling point of the pure solvent.

Freezing-Point Depression

A colligative property of a solution equal to the freezing point of the pure solvent minus the freezing point of the solution.

Osmosis

The phenomenon of solvent flow through a semipermeable membrane to equalize the solute concentration on both sides of the membrane.

Osmotic Pressure

The pressure that, when applied, just stops osmosis; a colligative property of a solution.

Hypertonic Solution

Water flows out of the cell.

Hypotonic Solution

Water flows into of the cell.

Isotonic Solution

Concentration is balanced.

Semipermeable membrane

Allows solvent molecules to pass through, but not solute molecules.