absolute zero
the temperature at which all molecular motion should cease
(two words)
accelerator
a device that is used to accelerate charged particles to high speeds
accuracy
the relationship between the graduations on a measuring device and the actual standard for the quantity being measured
acid
a substance that produces hydrogen ions in water solution; a proton donor
acidic anhydride
a nonmetallic oxide that can react with water to form an acid
(two words)
actinoid series
fourteen elements beginning with actinium in which the arrow diagram predicts the highest energy electrons to be in the 5f sublevel
(two words)
activated complex
an assembly of atoms in an excited state between reactants and products in a chemical reaction
(two words)
activation energy
the [energy] required to form the activated complex
(two words)
activity
the effective concentration of a species
addition polymerization
the formation of a polymer through addition reactions
(two words)
addition reaction
a [reaction]; the combining of two or more molecules through adding on at the double or triple bond of an unsaturated organic compound
(two words)
adiabatic system
[system] in which heat neither leaves nor enters
(two words)
adsorption
the process of one substance being attracted and held to the surface of another substance
alcohol
one of a class of organic compounds characterized by the presence of the hydroxyl group, -OH
aldehyde
one of the class of organic compounds characterized by the presence of the carbonyl group (>C = 0) on the end of the carbon chain(RCHO)
aliphatic
hydrocarbons consisting of chains or nonaromatic rings
alkali metal
an element in Group 1(IA)
(two words)
alkaline earth metal
an element in Group 2(IIA)
(three words)
alkane
an aliphatic hydrocarbon having only single carbon-carbon bonds
alkene
an aliphatic hydrocarbon having one or more double bonds
alkyne
an aliphatic hydrocarbon having one or more triple bonds
allotrope
form of an element differing in crystal or molecular structure
alloy
a mixture of a metal and one or more other elements, usually metals
alpha particle
a helium nucleus
(two words)
amide
an organic compound containing the -CO-NH2 group; an inorganic compound containing NH2
amine
an organic compound derived from ammonia by replacement of one or more hydrogen atoms by hydrocarbon radicals
amino acid
an organic compound characterized by the presence of an amino group and a carboxyl group on the same carbon atom
(two words)
amorphous
a non-crystalline material that appears solid but without long-range order; supercooled liquid
ampere
the unit of electric current equal to one coulomb per second
amphoteric
having the ability to act as either an acid or a base
amplitude
the maximum value attained by a wave
anhydrous
without water
anion
a negative ion
anode
the positive electrode (general); the electrode at which oxidation occurs (electrochemical)
antiparticle
a particle identical to a second particle in all respects except for opposite charge and magnetic moment
aromatic compound
an organic ring [compound] containing one or more benzene rings
(two words)
arrow diagram
a system for predicting the order of filling energy sublevels with electrons
(two words)
atom
the smallest particle of an element
atomic mass
the [mass] of an atom in atomic mass units; the average mass of the atoms of an element
(two words)
atomic mass unit
one-twelfth the mass of the carbon-12 atom
(three words)
atomic number
the [number] of protons in the nucleus of an atom
(two words)
atomic radius
the distance from the center of an atom to the 90% probability surface of the electron cloud
(two words)
atomic theory
the body of knowledge concerning the existence of atoms and their characteristic structure
(two words)
Avogadro constant
the number of objects in a mole; 6.022 136 7 x 10^23
(two words)
Avogadro's principle
The [principle] that equal volumes of gases at the same temperature and pressure contain the same number of molecules.
(two words, possessive)
balance
an instrument used to measure mass
barometer
a manometer used to measure atmospheric pressure
baryon
a subatomic particle classified as a heavy hadron
base
a substance that produces hydroxide ions in water solution; a proton acceptor
basic anhydride
a metallic oxide that will react with water to form a base
(two words)
beta particle
an electron (-) or positron (+)
(two words)
binary acid
an [acid] containing only hydrogen and one other element
(two words)
binary compound
a [compound] composed of only two elements
(two words)
binding energy
the [energy] required to split the nucleus into separate nucleons
(two words)
biochemistry
the study of the substances and reactions involved in life processes
body-centered cubic
having a unit cell with a particle at each vertex of a cube and a particle in the center of the cube
(three words, hyphenated)
Bohr atom
planetary [atom] model
(two words)
boiling point
the temperature at which the vapor pressure of a liquid equals the atmospheric pressure
(two words)
bond
the force holding atoms together in a compound or molecule
bond angle
the [angle] between two bond axes extending from the same atom
(two words)
bond axis
the imaginary line connecting the nuclei of two bonded atoms
(two words)
bond character
the relative ionic or covalent nature of a chemical bond
(two words)
bond length
the distance between the nuclei of bonded atoms
(two words)
bond strength
the energy required to break a bond
(two words)
Boyle's law
The volume of a specific amount of gas varies inversely as the pressure if the temperature remains constant.
(two words, possessive)
branch
a carbon group, named as a radical, that is attached to the main carbon chain in an organic compound
Brownian motion
the random [motion] of colloidal particles due to their bombardment by the molecules of the dispersing medium
(two words)
buffer system
a solution that can receive moderate amounts of either acid or base without significant change in its pH.
(two words)
calorimeter
a device for measuring the transfer of heat during a chemical or physical change
capillary rise
the tendency of a liquid to [rise] in a tube of small diameter due to the surface tension of the liquid
(two words)
carbide ion
a carbon atom that has gained four electrons; C^4-
(two words)
carbohydrate
compounds of carbon, hydrogen, and oxygen that are mostly simple sugars or condensation polymers of sugars
carboxylic acid
the class of organic compounds characterized by the carboxyl group (-COOH)
(two words)
catalysis
the speeding up of chemical reactions by the presence of a substance that is unchanged after the reaction
catalyst
a substance that speeds a chemical reaction without being permanently changed itself
catenation
the joining of like atoms in chains.
cathode
the negative electrode (general); the electrode at which reduction occurs (electrochemical)
cathode rays
the beam of electrons in a gas discharge tube
(two words, plural)
cation
a positive ion
cell potential
the voltage obtained from a voltaic cell
(two words)
cellulose
a woody polymer of glucose
Celsius scale
the temperature scale based on the boiling point of water as 100 degrees and the freezing point of water as 0 degrees
(two words)
chain reaction
a [reaction] in which the product from each step acts as a reactant for the next step
(two words)
chalcogen
an element in Group 16(VIA)
Charles's law
The volume of a specific amount of gas varies directly as the absolute temperature if the pressure remains constant.
(two words, possessive)
chemical change
a [change]; a rearrangement of atoms and/or molecules to produce one or more new substances with new properties
(two words)
chemical formula
the notation using symbols and numerals to represent the composition of substances
(two words)
chemical property
a [property] characteristic of a substance when it is involved in a chemical change
(two words)
chemical reaction
a [reaction] in which one or more substances are changed into one or more new substances
(two words)
chemical symbol
a notation using one to three letters to represent an element
(two words)
chemistry
the study of the structure and properties of matter
chromatography
the separation of a mixture using a technique based upon differential adsorption between a stationary phase and a mobile phase
closest packing
the crystal structure in which space between particles is minimized
(two words)
coefficient
a numeral, representing the number of formula units of the substance, placed before a formula
colligative properties
the [properties] of solutions that depend only on the number of particles present without regard to type
(two words, plural)
colloid
a dispersion of particles from 1 nm to 100 nm in at least one dimension in a continuous medium
colloid chemistry
the study of colloids, especially of surfaces
(two words)
column chromatography
[chromatography] in which the stationary phase is held in a column
(two words)
combustion
burning, or reaction with oxygen producing heat and usually light
common ion effect
an equilibrium phenomenon in which an ion common to two or more substances in a solution shifts the point of equilibrium away from itself
(three words)
complex ion
a central positive [ion] surrounded by bonded ligands
(two words)
compound
a substance composed of atoms of two or more elements linked by chemical bonds
concentrated solution
a solution with a high ratio of solute to solvent
(two words)
concentration
the ratio of the amount of solute to the amount of solvent or solution
condensation polymerization
the formation of a polymer and a small molecule, usually water, from monomers
(two words)
condensed state
solid or liquid
(two words)
conductivity
the relative ability to conduct heat and electricity
conjugate acid
the particle obtained after a base has gained a proton
(two words)
conjugate base
the particle remaining after an acid has donated a proton
(two words)
conjugated system
a group of four or more adjacent atoms in a molecule with an extended pi-bonding system
(two words)
consumer product
an item for sale to the general public
(two words)
contact catalyst
a [catalyst] that functions by adsorbing one of the reactants on its surface; a heterogeneous catalyst
(two words)
containment vessel
a reinforced concrete and steel structure designed to contain any leakage from a nuclear reactor
(two words)
continuous phase
the dispersing medium in a colloid
(two words)
control rod
the neutron-absorbing substance used to control the rate of reaction in a nuclear reactor
(two words)
coordinate covalent bond
a covalent [bond] in which both electrons of the shared pair come from the same atom
(three words)
coordination number
the [number] of points at which ligands are attached to the central atom or ion in a complex ion or coordination compound
(two words)
corrosion
the chemical interaction of a metal with its environment
coulomb
the quantity of electrical charge equal to the flow of one ampere for one second
counting number
natural [number]; any cardinal number except zero
(two words)
covalent bond
a [bond] characterized by the sharing of one or more pairs of electrons between two atoms
(two words)
covalent radius
the [radius] of an atom along the bond axis
(two words)
critical pressure
the [pressure] needed to liquefy a gas at its critical temperature
(two words)
critical temperature
the highest [temperature] at which the vapor and liquid states of a substance can exist in equilibrium
(two words)
crystal
a solid in which the particles are arranged in a regular, repeating pattern; a lattice
crystal defect
an imperfection in a crystal lattice
(two words)
crystallization
the forming of crystals by evaporation or cooling
crystalloid
a substance that can penetrate a semipermeable membrane
cubic closest packing
face-centered cubic
(three words)
cyclic
consisting of atoms bonded in a closed ring
cycloalkanes
hydrocarbons in which the carbon atoms are bonded in a ring and all bonds are single bonds
(plural)
Dalton's law
In a mixture of gases, the total pressure of the mixture is the sum of the partial pressures of each component gas.
(two words, possessive)
de Broglie's hypothesis
the [hypothesis] that particles may have the properties of waves.
(two words, possessive)
decomposition
a reaction in which a compound breaks into two or more simpler substances
degenerate
having the same energy
dehydrating agent
a substance that can absorb water from other substances
(two words)
deliquescent
the property of a solid to absorb sufficient water from the air to form a liquid solution
delocalization
the concept in which bonding electrons are not confined to the region between two atoms, but may be spread over several atoms or a whole piece of metal
density
mass per unit volume
desiccant
a drying agent
didentate
a ligand that attaches to the central ion in a complex in two places
diffusion
the spontaneous spreading of particles throughout a given volume until they are uniformly distributed
dilute solution
a [solution] with a low ratio of solute to solvent
(two words)
dipeptide
two amino acids joined by an amide link
dipole
a polar molecule
dipole-dipole force
an attraction between dipoles; component of van der Waals forces
(three words, hyphenated)
dipole-induced dipole force
an attraction between a dipole and a nonpolar molecule that has been induced to become a dipole; component of van der Waals forces
(four words, hyphenated)
dipole moment
the strength of a dipole expressed as charge multiplied by distance
(two words)
dislocation
a crystal defect
dispersed phase
colloidal particles distributed throughout the continuous phase
(two words)
dispersion forces
the [forces] between particles that are not permanent dipoles; component of van der Waals forces
(two words, plural)
dissociation
the separation of ions in solution
distillation
a separation method based on the evaporation of a liquid and the condensation of its vapor
doping
the addition of impurities to a semiconductor to increase electrical conductivity
double bond
a covalent [bond] in which two atoms share two pairs of electrons
(two words)
double displacement
a chemical reaction in which the positive part of one compound combines with the negative part of another compound, and vice versa
(two words)