Ch 15: Water and Aqueous Systems

surface tension

the inward force, or pull, that tends to minimize the surface area of a liquid

durfactant

any substance that interferes with the hydrogen bonding between water molecules and thereby reduces surface tension

aqueous solution

water that contains dissolved substances

solvent

the dissolving medium

solute

the dissolved particles in a solution

solvation

the process by which the positive and negative ions of an ionic solid become surrounded by solvent molecules

electrolyte

a compound that conducts an electric current when it is in an aqueous solution or in the molten state

nonelectrolyte

a compound that does not conduct an electric current in either an aqueous solution or the molten state

strong electrolyte

a solution in which a large portion of the solute exists as ions

weak electrolyte

a solution that conducts electricity poorly because only a fraction of the solute exists as ions

water of hydration

water contained in a crystal

hydrate

a compound that contains water of hydration

anhydrous

a substance that does not contain water

effloresce

to lose water of hydration; the process occurs when the hydrate has a vapor pressure higher than that of water vapor in the air

hygroscopic

a term describing salts and other compounds that remove moisture from the air

desiccant

a substance used to absorb moisture from the air and create a dry atmosphere

suspension

a mixture from which particles settle out pon standing

colloid

a heterogeneous mixture containing particles that range in size from 1 nm to 1000 nm

Tyndall effect

the scattering of visible light by colloidal particles

Brownian motion

the chaotic movement of colloidal particles, caused by collision with particles of the solvent in which they are dispersed

emulsion

a colloidal dispersion of a liquid in a liquid