Key Terms

alloy

solid mixture of a metallic element and one or more additional elements

amphiphilic

molecules possessing both hydrophobic (nonpolar) and a hydrophilic (polar) parts

boiling point elevation

elevation of the boiling point of a liquid by addition of a solute

boiling point elevation constant

the proportionality constant in the equation relating boiling point elevation to solute molality; also known as the ebullioscopic constant

colligative property

property of a solution that depends only on the concentration of a solute species

colloid

(also, colloidal dispersion) mixture in which relatively large solid or liquid particles are dispersed uniformly throughout a gas, liquid, or solid

crenation

process whereby biological cells become shriveled due to loss of water by osmosis

dispersed phase

substance present as relatively large solid or liquid particles in a colloid

dispersion medium

solid, liquid, or gas in which colloidal particles are dispersed

dissociation

physical process accompanying the dissolution of an ionic compound in which the compound’s constituent ions are solvated and dispersed throughout the solution

electrolyte

substance that produces ions when dissolved in water

emulsifying agent

amphiphilic substance used to stabilize the particles of some emulsions

emulsion

colloid formed from immiscible liquids

freezing point depression

lowering of the freezing point of a liquid by addition of a solute

freezing point depression constant

(also, cryoscopic constant) proportionality constant in the equation relating freezing point depression to solute molality

gel

colloidal dispersion of a liquid in a solid

hemolysis

rupture of red blood cells due to the accumulation of excess water by osmosis

Henry’s law

law stating the proportional relationship between the concentration of dissolved gas in a solution and the partial pressure of the gas in contact with the solution

hypertonic

of greater osmotic pressure

hypotonic

of less osmotic pressure

ideal solution

solution that forms with no accompanying energy change

immiscible

of negligible mutual solubility; typically refers to liquid substances

ion pair

solvated anion/cation pair held together by moderate electrostatic attraction

ion-dipole attraction

electrostatic attraction between an ion and a polar molecule

isotonic

of equal osmotic pressure

miscible

mutually soluble in all proportions; typically refers to liquid substances

molality (m)

a concentration unit defined as the ratio of the numbers of moles of solute to the mass of the solvent in kilograms

nonelectrolyte

substance that does not produce ions when dissolved in water

osmosis

diffusion of solvent molecules through a semipermeable membrane

osmotic pressure (Π)

opposing pressure required to prevent bulk transfer of solvent molecules through a semipermeable membrane

partially miscible

of moderate mutual solubility; typically refers to liquid substances

Raoult’s law

the partial pressure exerted by a solution component is equal to the product of the component’s mole fraction in the solution and its equilibrium vapor pressure in the pure state

saturated

of concentration equal to solubility; containing the maximum concentration of solute possible for a given temperature and pressure

semipermeable membrane

a membrane that selectively permits passage of certain ions or molecules

solubility

extent to which a solute may be dissolved in water, or any solvent

solvation

exothermic process in which intermolecular attractive forces between the solute and solvent in a solution are established

spontaneous process

physical or chemical change that occurs without the addition of energy from an external source

strong electrolyte

substance that dissociates or ionizes completely when dissolved in water

supersaturated

of concentration that exceeds solubility; a nonequilibrium state

Tyndall effect

scattering of visible light by a colloidal dispersion

unsaturated

of concentration less than solubility

van’t Hoff factor (i)

the ratio of the number of moles of particles in a solution to the number of moles of formula units dissolved in the solution

weak electrolyte

substance that ionizes only partially when dissolved in water