Chemistry Chapter 12 and 13 VOCAB

Adhesion

attraction to unliked molecules

Amorphous solid

a solid that lacks a regular 3d arrangement of atoms or molecules

Boiling point

the temperature at which the vapor pressure of a liquid is equal to the external atmospheric pressure

Closest packing

the most efficient arrangement for packing atoms, molecules, or ions in a crystal

Cohesion

the intermolecular attraction between like molecules

Condensation

the phenomenon of going from a gaseous state to the liquid state

Coordination number

In a crystal lattice it is defi ned as the number of atoms (or ions) surrounding an atom (or ion) (12.4). In coordination compounds it is defi ned as the number of donor atoms surrounding the central metal atom in a complex

Critical Pressure (Pc)

The minimum pressure necessary to bring about liquefaction at the critical temperature

Critical Temperature (Tc)

the temperature above which a gas will not liquefy

Crystalline Solid

A solid that possesses rigid and long-range structural order; its atoms, molecules, or ions occupy specifi c positions.

Deposition

The process in which vapor molecules are converted directly to the solid phase

Dipole-dipole forces

forces that act between polar molecules

Dispersion forces

The attractive forces that arise as a result of temporary dipoles induced in the atoms or molecules.

Dynamic equilibrium

The condition in which the rate of a forward process is exactly balanced by the rate of the reverse process

Evaporation vapor pressure

Evaporation

The escape of molecules from the surface of a liquid; also called vaporization

Hydrogen Bond

A special type of dipole-dipole interaction between the hydrogen atom bonded to an atom of a very electronegative element (F, N, O) and another atom of one of the three electronegative elements

Induced dipole

The separation of positive and negative charges in an atom (or a nonpolar molecule) caused by the proximity of an ion or a polar molecule

Intermolecular forces

attractive forces that exist among molecules

Intramolecular forces

forces that hold atoms together in a molecule

Ion-diople forces

forces that operate between an ion and a dipole

lattice point

The positions occupied by atoms, molecules, or ions that defi ne the geometry of a unit cell.

melting point

The temperature at which solid and liquid phases coexist in equilibrium.

molar heat of fusion (DELTAHfus)

The energy (in kilojoules) required to melt 1 mole of a solid

Molar heat sublimation (DELTABHsub)

The energy (in kilojoules) required to sublime 1 mole of a solid

Molar heat vaporization (DELTABHvap)

The energy (in kilojoules) required to vaporize 1 mole of a liquid

Phase

A homogeneous part of a system that is in contact with other parts of the system but separated from them by a well-defi ned boundary

Phase Changes

transformation from one phase to another

Phase diagram

a diagram showing the conditions at which a substance exists as a solid, liquid, and vapor

Polarizability

The ease with which the electron distribution in the atom (or molecule) can be distorted

Sublimation

The process in which molecules go directly from the solid phase into the vapor phase

surface tension

The amount of energy required to stretch or increase the surface of a liquid by a unit area

triple point

The point at which the vapor, liquid, and solid states of a substance are in equilibrium

unit cell

the basic repeating unit of the arrangement of atoms, molecules, or ions in a crystalline solid

Van der Waals forces

The collective name for certain attractive forces between atoms and molecules, namely, dipole-dipole, dipole-induced dipole, and dispersion forces

Vaporization

The escape of molecules from the surface of a liquid: also called evaporation

Viscosity

measure of a fluid’s resistance to flow

X-ray diffraction

The scattering of X rays by the units of a regular crystalline solid

colligative properties

Properties of solutions that depend on the number of solute particles in solution and not on the nature of the solute

crystallization

The process in which dissolved solute comes out of solution and forms crystals.

Henry’s law

The solubility of a gas in a liquid is proportional to the pressure of the gas over the solution

ideal solution

Any solution that obeys Raoult’s law

ion pair

A species made up of at least one cation and at least one anion held together by electrostatic forces

miscible

Two liquids that are completely soluble in each other in all proportions are said to be XXX.

molality

The number of moles of solute dissolved in 1 kilogram of solvent

nonvolatile

Does not have a measurable vapor pressure.

osmotic pressure (pi)

the pressure required to stop osmosis

percent by mass

the ratio of the mass of a solute to the mass of the solution, multiplied by 100%

raoult’s law

The partial pressure of the solvent over a solution is given by the product of the vapor pressure of the pure solvent and the mole fraction of the solvent in the solution

saturated solution

At a given temperature, the solution that results when the maximum amount of a substance has dissolved in a solvent

semipermeable membrane

A membrane that allows solvent molecules to pass through, but blocks the movement of solute molecules

solvation

the process in which an ion or molecule is surrounded by solvent molecules arranged in an ordered manner

supersaturated solution

A solution that contains more of the solute than is present in a saturated solution

thermal pollution

The heating of the environment to temperatures that are harmful to its living inhabitants

unsaturated solution

A solution that contains less solute than it has the capacity to dissolve

volatile

having a measurable vapor pressure