heat of vaporization the amount of energy required to bring about the boiling of a liquid at its normal boiling (condensation) temperature.

hydrogen bonding attractive force resulting from a hydrogen atom bridging between two small, electronegative atoms (such as F, O, or N atoms).

ice solid water.

intensive property a property that does not depend upon the amount of sample present, such as density, concentration, pressure, or specific heat.

intermolecular forces forces between molecules holding the molecules together in an aggregate; responsible for formation of condensed states in molecular substances.

kilojoule 1000 joules; one joule is the kinetic energy of a 1 kilogram object moving at a speed of 1 meter per second.

kinetic energy energy of motion.

latent heat heat of fusion or heat of vaporization; heat released (or taken in) during a change of state.

LeChatelierÕs principle when a stress is placed upon a system at equilibrium, the system shifts its equilibrium position so as to relieve the stress.

mass a fundamental property of matter that makes it subject to gravitational force. It is measured as a bodyÕs tendency to resist changes in its state of motion.

melting change from the solid to the liquid state.

melting point temperature at which melting occurs.

non-Newtonian fluid a fluid whose viscous behavior is not typical of common liquids but whose viscosity increases with increase in rate of flow. phase change change from one phase to another. When applied to substances not undergoing chemical changes, this refers to melting, freezing, boiling, condensing, or subliming.

phase diagram plot of pressure versus temperature for a substance indicating the states of matter present at each point by labelling regions as solid, liquid, or vapor. Several solids and sometimes more than one liquid are possible.

physical change change that does not involve changing chemical bonds such as change of state for a substance.

physical property property relating to physical changes or state (such as melting point or density).

potential energy energy of position. Latent heats are examples of potential energy, as are changes in energy due to changes in chemical bonding.

pure substance one element or compound.

slope the ratio of the increase in the y-increment for a given x-increment in a straight line graph.

specific gravity the ratio of the mass of a given volume of material to the mass of the same volume of water.

specific heat the amount of heat required to raise the temperature of one gram of a material by one Celsius degree.

sublimation change from the solid to the gaseous state.

surface tension molecules on the surface of a liquid experience different forces than those in the interior that are surrounded by other molecules. The surface acts as if it experiences a tension or force as a result.