Term | Definition |
intermolecular forces | the short-range attractive forces operating between the particles that make up the units of a liquid or solid substance. These same forces also cause gases to liquefy or solidify at low temperatures and high pressures |
dipole-dipole forces | the force that exists because of the interactions of dipoles on polar molecules in close contact |
London dispersion forces | intermolecular forces resulting from attractions between induced dipoles |
hydrogen bonding | bonding that results from intermolecular attractions between molecules containing hydrogen bonded to an electronegative element
NOF |
Ion-dipole force | the force that exists between an ion and a neutral polar molecule that possesses a permanent dipole moment |
polarizability | the ease with which the electron cloud of anatomy or a molecule is distorted by an outside influence, thereby inducing a dipole moment |
viscosity | a measure of the resistance of fluids to flow |
surface tension | the intermolecular, cohesive attraction that causes a liquid to minimize its surface area |
capillary action | the process by which a liquid rises in a tube because of a combination of adhesion to the walls of the tube and cohesion between liquid particles |
phase change | the conversion of a substance from one stage of matter to another. the phase changes we consider are melting and freezing, sublimation and disposition, and vaporization and condensation. |
heat of fusion | the enthalpy change, delta H, for melting a solid |
heat of sublimation | the enthalpy change, delta H, for vaporization of a solid |
heat of vaporization | the enthalpy change, delta H, for vaporization of a liquid |
critical temperature | the highest temperature at which it is possible to convert the gaseous form of a substance to a liquid. the critical temperature increases with an increase in the magnitude of intermolecular forces |
critical pressure | the pressure at which a gas at its critical temperature is converted to a liquid state |
vapor pressure | the pressure exerted by a vapor in equilibrium with its liquid or solid phase |
dynamic equilibrium | a state of balance in which opposing processes occur at the same rate |
volatile | tending to evaporate readily |
normal boiling point | the boiling point at 1 atm pressure |
phase diagram | a graphic representation of the equilibria among the solid, liquid, and gaseous phases of a substance as a function of temperature and pressure |
normal melting point | the melting point at 1 atm pressure |
triple point | the temperature at which solid, liquid, and gas phases coexist in equilibrium |
crystalline solid (crystal) | a solid whose internal arrangement of atom, molecules, or ions shows a regular repetition in any direction through the solid |
amorphous solid | a solid whose molecular arrangement lacks a regular, long-range pattern |
unit cell | the smallest portion of a crystal that reproduces the structure of the entire crystal when repeated in different directions in space. it is the repeating hit of building block of the crystal lattice |
crystal lattice | an imaginary network of points on which the repeating unit of the structure of a solid may be imagined to be laid down so that the structure of the crystal is obtained. each point represents an identical environment in the crystal |
primitive cubic cell | a cubic unit cell in which the lattice points are at the corners only |
body-centered cubic cell | a cubic unit cell in which the lattice points occur at the corners and at the center |
face-centered cubic cell | a cubic unit cell that has lattice points at each corner as well as at the center of each face |
cubic close packing | a close-packing arrangement in which the atoms of the third layer of a solid are not directly over those in the first layer |
hexagonal close packing | a close-packing arrangement in which the atoms of the third layer of a solid lie directly over those in the first layer |
coordination number | the number of adjacent atoms to which an atom is directly bonded. in a complex the coordination number of the metal ion is the number of donor atoms to which it is bonded |
molecular solids | solids that are composed of molecules |
covalent-network solids | solids in which the units that make up the three-dimensional network are joined by covalent bonds |
ionic solids | solids that are composed of ions |
metallic solids | solids that are composed of metal atoms |