The section numbers in which the terms are explained are given in parentheses.

absolute temperature (12.3) A temperature, measured on the Kelvin scale, that must be used for gas law and certain other types of calculations.

absolute zero (12.3) 0 K, the lowest possible temperature.

accuracy (2.3) The closeness of a measurement or set of measurements to the correct value.

acetone (19.3) CH3COCH3, propanone, the simplest ketone.

acetylene (19.1) HCPCH, ethyne, the simplest alkyne.

acid (6.3, 8.4) A compound that provides H1 ions to water solutions. (See also Brønsted acid and organic acid.)

acid carbonate (8.4) A compound containing the HCO32 ion.

acid dissociation constant (18.2) The equilibrium constant that controls the extent of ionization of a weak acid in water; symbolized by Ka.

acid salt (6.3, 8.4) A partially neutralized acid that originally contained two or more ionizable hydrogen atoms per molecule; for example, HSO42 is partially neutralized H2SO4.

acid strength (18.1) The tendency for a certain percentage of acid molecules to ionize in water; the higher the acid strength, the higher is the percent ionization.

acidic anhydride (8.4) A nonmetal oxide that can react with water to form an acid.

active (8.3) Having a high tendency to react; reactive.

alcohol (19.3) An organic compound with the ±OH functional group.

aldehyde (19.3) An organic compound with the ±CHO functional group.

alkali metal (1.5) A metal in group IA of the periodic table—Li, Na, K, Rb, Cs, or Fr.

alkaline earth metal (1.5) A metal in group IIA of the periodic table—Be, Mg, Ca, Sr, Ba, or Ra.

alkane (19.1) A hydrocarbon containing only single bonds.

alkene (19.1) A hydrocarbon containing one double bond per molecule.

alkyl radical (19.3) A portion of an alkane formed by loss of one hydrogen atom.

alkyne (19.1) A hydrocarbon containing one triple bond per molecule.

allotrope (5.5) One of two or more forms of an uncombined element; for example, diamond and graphite are allotropes of carbon.

alpha particle (20.1) A helium nucleus generated in a nuclear reaction; a stream of such particles is referred to as an alpha ray.

amide (19.3) An organic compound with the ±CONH± functional group.

amine (19.3) An organic compound with the ±NR2 functional group, where either or both R groups can be hydrogen atoms.

ammonia (6.1) The covalent compound NH3.

ammonium ion (6.2) The NH41 ion.

amorphous solid (14.1) A solid with an internal structure that does not repeat over many molecules and that therefore has a large melting range.

amphiprotic (18.1) The ability of a molecule or ion to react with both acids and bases.

analytical chemistry (Chapter 1, Introduction) The branch of chemistry dealing with the composition of samples.

angular molecule (13.4) A three-atom molecule in which the atoms do not lie on a line.

angular momentum quantum number (4.3) The quantum number (,) that governs the shape of the space occupied by an electron in an atom.

anhydride (8.4) A compound resulting from loss of water by another compound; for example, the CaO resulting from strong heating of Ca(OH)2.

anhydrous (5.1) Without water; for example, CuSO4 resulting from loss of water from CuSO4·5H2O is said to be anhydrous.

anion (5.2) A negatively charged ion.

anode (5.2) The electrode where oxidation occurs in an electrochemical reaction.

aqueous solution (8.2) Any solution in which water is the solvent.

aromatic hydrocarbon (19.1) A hydrocarbon containing one or more benzene rings.

Arrhenius acid (8.4) A compound that provides H1 ions to water.

Arrhenius base (8.4) A compound that provides OH2 ions to water.

Arrhenius theory (8.4) The fundamental theory of acids and bases. (Contrast with Brønsted theory.)

atmosphere (12.1) A unit equal to 760 torr and abbreviated atm that is the pressure of the atmosphere on a "normal" day at sea level; the envelope of air surrounding the earth.

atmospheric pressure (12.1) The pressure of the atmosphere.

atom (3.2) The smallest particle that retains the characteristic composition of an element.

atom smasher (20.3) A machine designed to initiate nuclear reactions.

atomic bomb (20.3) A nuclear bomb; a bomb in which matter is converted to energy for destructive purposes.

atomic mass (3.4, 7.1) The weighted average of the masses of the naturally occurring isotopes of an element, compared to one-twelfth of the mass of a 12C atom.

atomic mass scale (3.4) A relative scale of masses based on the mass of 12C being the standard and having a mass defined as exactly 12 amu.

atomic mass unit (3.4) A mass equal to one-twelfth of the mass of a 12C atom; abbreviated amu.

atomic number (3.3) The number of protons in the nucleus of each atom of an element.

atomic size (13.1) The size of an atom.

atomic theory See Dalton’s atomic theory.

atomic weight See atomic mass.

atomic weight scale (3.4) Atomic mass scale.

autoionization (18.3) A reaction of molecules of a single substance to produce both positive and negative ions; for example, water molecules react to produce both H3O1 and OH2 ions.

auto-oxidation reduction See disproportionation.

average kinetic energy (12.10) The total kinetic energy of all the molecules of a sample, divided by the number of molecules; the average kinetic energy is dependent on temperature only.

Avogadro’s number (7.3) 6.02 3 1023, which is the number of 12C atoms in exactly 12 g of 12C (as well as the number of atomic mass units in exactly 1 g).

balanced equation (8.1) A written representation of a chemical reaction in which formulas of the reactants and products appear on two sides of an arrow, with coefficients to make the numbers of atoms of each element the same on both sides.

barometer (12.1) An instrument for measuring the pressure of a gas, especially the atmosphere.

barometric pressure (12.1) The pressure of the atmosphere.

base (6.3, 8.4) A compound that provides OH2 ions to water solutions. (See also Brønsted base.)

base (2.4) The number that is raised to a power and multiplied by a coefficient in an exponential number; for example, the 10 in 1.5 3 102.

base dissociation constant (18.2) The equilibrium constant that controls the extent of ionization of a weak base in water; symbolized Kb.

base strength (18.1) The tendency for a certain percentage of molecules of a base to ionize in water; the higher the base strength, the higher is the percent ionization.

basic anhydride (8.4) A metal oxide that can react with water to form a base.

battery (16.5) A combination of two or more galvanic cells.

bent molecule (13.4) See angular molecule.

benzene (19.1) C6H6, the simplest aromatic hydrocarbon.

beta particle (20.1) A high-energy electron emitted from a nucleus in a nuclear reaction; a stream of such particles is called a beta ray.

binary compound (5.1) A compound composed of two elements.

biochemistry (Chapter 1, Introduction) The branch of chemistry dealing with living things.

Bohr theory (4.2) The first theory of the atom to propose that electrons in atoms were in definite energy levels.

boiling point (14.2) The temperature at which a liquid changes to a gas at the prevailing pressure.

boiling-point elevation (15.5) An increase in the boiling point of a solvent due to the presence of a solute.

bond See covalent bond and ionic bond.

bond order See total bond order.

Boyle’s law (12.2) At constant temperature, the volume of a given sample of gas is inversely proportional to its pressure.

Brønsted acid (18.1) A proton donor.

Brønsted base (18.1) A proton acceptor.

Brønsted theory (18.1) A theory of acids and bases that is broader than the Arrhenius theory in that it does not limit acids and bases to water solutions and it defines ions as acids or bases depending on their tendency to react with water.

buffer solution (18.4) A solution of a weak acid and its conjugate base or a weak base and its conjugate acid, which resists changes in its acidity even on addition of a moderate quantity of strong acid or strong base.

buildup principle (4.4) The addition of an electron to the configuration of an atom of the preceding element on the periodic table allows determination of the electronic configuration of an atom of a given element.

buret (11.3) A piece of laboratory glassware calibrated for measuring the volume of liquid delivered.

calorie (2.6) A unit of energy equal to the quantity of heat necessary to raise the temperature of 1 g of water by 18C; equivalent to 4.184 J.

carbohydrate (19.5) A compound containing carbon plus hydrogen and oxygen in a mole ratio of 2:1; the general formula is CxH2yOy.

carbonate (8.4) An ionic compound containing the CO322 ion.

catalyst (8.3, 17.1) A material that affects the speed of a chemical reaction without any permanent change in its own composition.

cathode (5.2) The electrode where reduction occurs in an electrochemical reaction.

cation (5.2) A positively charged ion.

Celsius scale (2.6) The temperature scale defined with 08 as the freezing point of water and 1008 as the normal boiling point of water; the centigrade scale.

centered dot (5.1) An indication that water of hydration is part of a compound, as in CuSO4·5H2O.

centigrade scale (2.6) The Celsius scale.

central atom (13.4) The atom in a molecule or ion to which (most of) the other atoms are covalently bonded.

chain reaction (20.3) A nuclear reaction whose products cause the same reaction to occur again.

Charles’ law (12.3) At constant pressure, the volume of a given sample of gas is directly proportional to its absolute temperature.

chemical change (1.1) A chemical reaction.

chemical reaction (1.1) A change in which the composition (or structure) of one or more substances is altered.

chemistry (1.3) The study of the interaction of matter and energy and the changes that matter undergoes.

circuit (16.5) A closed path that electric charge can follow and get back to its original location. The word is related to the word circle, because if you follow the path from any point you get back where you started. In electrochemistry, the circuit is composed of solutions (through which ions carry the charge) and wires (through which electrons carry the charge).

coefficient (2.4) The number that is multiplied by a base raised to a certain power in a number written in exponential notation, such as the 1.5 in 1.5 3 102.

coefficient (8.1) The number placed before a formula in a chemical equation to balance the equation.

coinage metal (1.5) An element of periodic group IB—Cu, Ag, or Au.

colligative properties (15.5) Characteristics of solutions that are dependent on the concentration of solute particles and the nature of the solvent but not on the nature of the solute.

combination reaction (8.3) A reaction in which two substances combine to form one.

combined gas law (12.4) For a given sample of gas, the volume is directly proportional to the absolute temperature and inversely proportional to the pressure.

combustion (8.3) A reaction of an element or compound with oxygen at high temperature.

completion (10.4) The condition a reaction has reached when the limiting quantity of reactant has been used up.

compound (1.1) A chemical combination of elements that has a definite composition and its own set of properties.

concentration (11.1, 15.3) The quantity of solute per unit volume of solution or per unit mass of solvent.

condensation (14.2) A change of phase from gaseous to liquid or solid.

conjugate acid (18.1) The cation (or molecule) that results from the reaction of a base with a proton.

conjugate acid-base pair (18.1) A Brønsted acid and base that differ from each other by H1.

conjugate base (18.1) The anion (or molecule) that results from the loss of a proton by an acid.

constant composition See law of constant composition.

"control" of shared electrons (16.1) Assignment of the electrons in a covalent bond to the more electronegative atom of the bond.

control rod (20.3) A neutron-absorbing rod used to slow down nuclear reactions in commercial reactors.

conversion factor (2.1) A ratio equal to 1, which can be multiplied by a quantity to change its form without changing its value.

covalent bond (5.5) A bond resulting from electron sharing.

critical mass (20.3) The smallest mass capable of sustaining a nuclear chain reaction.

crystalline solid (14.1) A solid with a regular internal structure of repeating units and a definite melting point.

cubic meter (2.2) The volume of a cube that measures 1 m on each edge; the basic unit of volume in SI.

Dalton’s atomic theory (3.2) The theory that matter is made up of small particles (atoms) that have properties characteristic of an element.

Dalton’s law of partial pressures (12.9) The total pressure of a gas mixture is equal to the sum of the partial pressures of its components.

Daniell cell (16.5) A cell with zinc and copper electrodes.

daughter isotope (20.1) The large product of a natural radioactive decay event.

decay See radioactive decay.

decomposition reaction (8.3) A reaction in which one compound is broken down into two or more substances.

definite composition (1.1) The given ratio by mass of each element in a compound to any other element in the compound.

definite proportions See law of definite proportions.

degenerate (4.3) Having the same energy.

density (2.5) The mass per unit volume of a sample of matter.

deuterium (20.4) The isotope of hydrogen with mass number 2; symbolized 2H or D.

deuteron (20.4) A deuterium (2H) nucleus; symbolized d.

diatomic molecule (5.1) A molecule containing two atoms.

dimensional analysis See factor label method.

dipole (13.5) See dipole moment.

dipole moment (13.5) An unequal distribution of charge in a molecule resulting from unsymmetrical orientation of polar bonds; also referred to as a dipole.

direct proportionality (12.3) The relationship in which one variable changes by the same factor as another.

disaccharide (19.5) A sugar containing two simple sugar molecules.

discrete energy levels (4.2) Atomic energy levels that have specific energies.

disintegration (20.1) A reaction of an unstable nucleus.

disproportionation (16.4) The reaction of a species with itself to produce products having higher and lower oxidation numbers; also called auto-oxidation-reduction.

dissociation (Chapter 9, Introduction) Separation of ions from their close proximity in a solid lattice to a distance when dissolved in a solvent.

dissolve (1.2) To go into solution, making a homogeneous mixture.

distillation (14.2) The conversion of a liquid to a gas and then back to a liquid to separate it from impurities.

double bond (5.5) The sharing of two pairs of electrons between atoms.

double displacement reaction (8.3) The reaction of two compounds in which two other compounds are produced, as a result of a trade of the anions by the cations.

double substitution reaction (8.3) A double displacement reaction.

ductile (1.5) Capable of being drawn into a wire.

duet (5.2) A pair of electrons associated with a hydrogen, helium, lithium, or beryllium atom, resulting in the stable configuration of a noble gas (helium).

dynamic state (17.2) A state in which two opposite processes occur at equal rates.

Einstein’s equation (20.3) The equation E 5 mc2, which relates the energy produced to the mass of matter converted to energy in a nuclear reaction.

electrochemistry (16.5) The branch of chemistry dealing with the interaction of chemical reactions and electricity.

electrode (5.2) The solid portion of an electrochemical reaction apparatus at which a change from electron conduction to ion conduction, or vice versa, takes place.

electrolysis (16.5) Production of a chemical reaction by means of an electric current.

electrolysis cell (16.5) An apparatus in which electrical energy can be used to produce chemical reactions.

electromagnetic radiation (20.1) Any form of light energy—visible light, ultraviolet light, X rays, gamma rays, infrared radiation, or microwaves.

electromagnetic spectrum (4.1) The complete collection of electromagnetic waves, including visible light, infrared, ultraviolet, X rays, gamma rays, and microwaves.

electron (3.3) A negatively charged subatomic particle; a fundamental particle of nature.

electron affinity (13.2) The energy liberated when a gaseous atom acquires an electron to form a gaseous anion.

electron dot diagram (5.3) A pictorial model of an atom, molecule, or ion consisting of the symbol(s) for element(s) and dots representing the valence electrons.

electron group (13.4) A single electron pair, the four or six electrons in a double or triple bond, or rarely, a single electron, which are attached to a central atom of a molecule or polyatomic ion.

electron sharing (5.5) The sharing of electrons between atoms to form covalent bonds.

electronegativity (5.1, 13.3) The tendency of atoms involved in covalent bonds to attract electrons.

electronic charge (3.3) The charge on one electron, 1.60 3 10219 coulomb.

electronic configuration (4.5) The arrangement of the electrons in an atom, ion, or molecule.

electronic structure See electronic configuration.

electropositive (5.1) Having only a small tendency to attract the electrons in a covalent bond.

element (1.1) A substance that cannot be broken down into simpler substances by chemical means; one of the basic building blocks of which all matter is composed.

elemental (5.1) Existing as an element; not combined into any compound.

empirical formula (7.4) The simplest formula for a compound that shows the atomic ratio of elements in the compound.

end point (11.3) The point in a titration when the indicator signals that the reaction is complete.

endothermic process (14.3) A process in which energy is absorbed from outside the system.

energy (1.3) The capacity to do work.

energy level diagram (4.7) A graph in which horizontal lines represent the orbitals of an atom, those with higher energies toward the top, and in which arrows may be used to represent electrons.

enthalpy change (14.4) The heat (under certain familiar conditions) involved in a process; symbolized DH.

enthalpy of formation (14.4) The enthalpy change in the formation of a substance from its elements in their standard states; symbolized DHf.

enthalpy of fusion See heat of fusion.

enthalpy of vaporization See heat of vaporization.

enzyme (17.1) A biochemical catalyst.

equation (8.1) A written representation of a chemical reaction, using formulas for the reactants and products and coefficients to indicate the mole ratios involved.

equilibrium (17.2) The situation in which the reactants and the products are producing each other at the same rate.

equilibrium constant (17.4) A constant that tells how far a reaction will proceed until it reaches equilibrium.

equilibrium constant expression (17.4) The ratio of the product of the concentrations of the products divided by the product of the concentrations of the reactants, each raised to the power corresponding to its coefficient in the balanced equation: for a A 1 b B E c C 1 d D,

equivalent (16.6) The quantity of a substance that will react with or produce 1 mole of electrons in an oxidation-reduction reaction or 1 mole of hydrogen ions or hydroxide ions in an acid-base reaction.

equivalent mass (16.6) The mass in grams of 1 equivalent of a substance.

Erlenmeyer flask (11.3) A flask designed to allow swirling of the liquid contents without spillage.

ester (19.3) An organic compound with the ±COO±R functional group.

ether (19.3) An organic compound with the ±O± functional group.

ethylene (19.1) Ethene, H2CœCH2.

evaporation (14.2) A change of phase from liquid to gaseous.

event (20.1) A nuclear reaction involving one nucleus.

excess (10.4) The quantity of a reactant that exceeds that which can react with the limiting quantity of another reactant.

excited state (4.1) The state of an atom that has more energy than its lowest energy state. Electrons in higher than normal energy positions are the cause in the discussions in this text.

exothermic process (14.3) A process in which energy is transferred to the surroundings.

exponent (2.4) The number of times the base is multiplied by the coefficient; for example, in 1.5 3 103, the 1.5 is multiplied by 10 three times, where 3 is the exponent.

exponential notation (2.4) The format for writing large or small numbers that consists of the coefficient times a base raised to a power; for example, 1.5 3 103.

exponential part (2.4) The base raised to a power in an exponential number.

extensive property (1.2) A characteristic that depends on the quantity of the sample.

factor label method (2.1) A system that involves the use of units to indicate the proper arithmetic operation to perform; also called dimensional analysis.

Fahrenheit scale (2.6) A temperature scale in common use in the United States on which the freezing point of water is defined as 328F and the normal boiling point of water is defined as 2128F.

family (1.5) In the periodic table, a column that includes elements with similar chemical properties; a periodic group.

fat (19.5) A compound formed by the reaction of glycerine with long-chain fatty acids.

feeble acid (18.1) An acid that has no tendency to react with water; the conjugate of a strong base.

feeble base (18.1) A base that has no tendency to react with water; the conjugate of a strong acid.

fluidity (14.1) The characteristic of a gas or liquid that allows it to flow.

force (12.1) A push or a pull.

formaldehyde (19.3) Methanal, HCHO.

formula (1.4, 5.1) A combination of symbols and subscripts that identifies the composition of an element, compound, or ion.

formula mass (7.1) The relative mass of one formula unit compared to the mass of a 12C atom, which is defined as exactly 12 amu.

formula unit (5.1) The collection of atoms described by a chemical formula_an atom of an uncombined element, a molecule of a molecular compound, or the set of ions in the formula of an ionic compound.

formula weight (7.1) Formula mass.

freezing (14.2) Changing from a liquid to a solid.

freezing-point depression (15.5) A lowering of the freezing point of a solvent due to the presence of a solute.

frequency (4.1) The number of times a wave passes a certain point per second.

functional group (19.3) The characteristic group of atoms attached to a radical that gives a class of organic compounds its characteristic properties.

fusion (14.2) Melting, or changing from a solid to a liquid as a result of heating; see also nuclear fusion.

galvanic cell (16.5) A voltaic cell.

gamma particle (20.1) A particle (photon) of high-energy electromagnetic radiation (light) emitted from a nucleus in a nuclear reaction; a stream of such particles is often referred to as a gamma ray.

gas (12.1) A state of matter; a sample of matter that has its volume and shape determined by the volume and shape of its container.

Gay-Lussac’s law of combining volumes (12.8) The pressure of a given sample of gas at constant volume is directly proportional to its absolute temperature.

Geiger counter (20.1) An instrument for measuring radioactivity.

glycerine (19.5) The trialcohol with the formula CH2OHCHOHCH2OH.

gram (2.2) The primary unit of mass in the metric system; one-thousandth of the SI standard mass_the kilogram.

ground state (4.3) The lowest energy state of the set of electrons in an atom.

group (1.5) In the periodic table, a column that includes elements with similar chemical properties; a family.

halate (6.2) A chlorate, bromate, or iodate.

half-life (20.2) The period of time it takes for half of a radioactive sample to disintegrate naturally.

half-reaction (16.4) The oxidation or reduction half of a redox reaction.

half-reaction method (16.4) The method of balancing oxidation-reduction equations that involves the completion and balancing of the oxidation and reduction half-reactions separately, followed by the combining of the two.

halogen (1.5) An element of periodic group VIIA_F, Cl, Br, I, or At.

heat (2.6, 14.4) A form of energy.

heat capacity See specific heat.

heat of formation See enthalpy of formation.

heat of fusion (14.3) The heat required to change a given quantity of solid to the liquid state.

heat of vaporization (14.3) The heat required to change a given quantity of liquid to the gas state.

heating curve (14.3) A graph showing the temperature changes of a substance as a function of the quantity of heat added.

Heisenberg uncertainty principle (4.6) It is impossible to know exactly both the energy and the momentum of a subatomic particle at the same time.

Hess’s law (14.4) When two or more processes combine to give a resulting process, their enthalpy changes add up to give the enthalpy change for the resulting process.

heterogeneous mixture (1.1) A physical combination of substances having distinguishable parts.

homogeneous mixture (1.1) A physical combination of substances whose parts are not distinguishable, even with the best optical microscope; a solution.

Hund’s rule (4.7) The electrons in a partially filled subshell in an atom will occupy the orbitals singly as far as possible.

hydrate (5.1) A compound that has water molecules bonded in it.

hydrocarbon (8.3, 19.1) A compound containing only carbon and hydrogen.

hydrogen (1.5) The first element on the periodic table.

hydrogen (6.3) Word used in names of acid salts to indicate the hydrogen remaining, as in NaHCO3, sodium hydrogen carbonate.

hydrogen bomb (20.4) A thermonuclear device in which the nuclear fusion of a hydrogen isotope is the source of energy.

hydrogen bonding (13.6) The intermolecular force resulting from the attraction of a hydrogen atom on one molecule to a small, highly electronegative atom (F, O, or N) on another molecule (or the same molecule).

hydronium ion (18.1) The H3O1 ion.

hypothesis (1.6) A proposed explanation for a body of observed facts.

ideal gas law (12.5) The pressure, volume, number of moles, and temperature of a sample of gas can be related by the equation PV 5 nRT, where R 5 0.0821 L·atm/mol·K.

ideal solution (15.5) A solution that obeys Raoult’s law exactly.

indicator (11.3) A compound that has different colors in solutions of different acidities and that is used to signal the end of a titration.

inner transition element (1.5) An element with atomic number 58–71 or 90–103; a member of the lanthanide or actinide series.

inorganic chemistry (Chapter 1, Introduction) The branch of chemistry dealing with compounds other than those containing C–C and/or C–H bonds.

intensive property (1.2) A characteristic such as color that does not depend on the quantity of material present.

intermolecular force (13.6) An attraction between molecules.

inverse proportionality (12.2) A relationship in which one variable gets smaller by the same factor as another gets larger, or vice versa.

ion (5.2) A charged atom or group of atoms.

ionic bond (5.2) The attractive force between oppositely charged ions.

ionic equation (9.2) A chemical equation in which soluble, ionic substances are written with their ions separated.

ionic size (13.1) The size of an ion.

ionic solid (14.1) A solid consisting of ions.

ionizable hydrogen atom (6.3) Any of the hydrogen atoms in an acid that are capable of reacting with water to form ions.

ionization (18.2) Reaction of a covalent substance with solvent to produce ions, as, for example, the reaction of a strong acid with water.

ionization constant (18.2) The equilibrium constant for the reaction of a weak acid or base with water to form ions in solution; symbolized Ki.

ionization energy (13.2) The energy required to remove an electron from a gaseous atom to form a gaseous cation.

isomers (19.2) Different compounds having the same molecular formula.

isotopes (3.3, 20.1) Two or more forms of an element whose atoms all have the same number of protons but different numbers of neutrons.

joule (2.6) The SI unit of energy; it takes 4.184 J to raise the temperature of 1.000 g of water 1.000°C.

kelvin (12.3) The unit of the Kelvin temperature scale; abbreviated K.

Kelvin scale (2.6, 12.3) The temperature scale with 273 as the freezing point of water and 373 as the normal boiling point of water; the scale required for gas law and certain other scientific calculations.

ketone (19.3) A class of organic compounds with the

CœO functional group not at the end of a carbon chain.

kilogram (2.2) 1000 grams; the standard mass in SI.

kinetic energy (12.10) Energy of motion; KE 5.

kinetic molecular theory (12.10) The theory that explains the gas laws (and other phenomena) in terms of the motions and characteristics of the molecules of a gas.

law (1.6) A generalized statement that summarizes a collection of observations.

law of conservation of energy (1.3) Energy can be neither created nor destroyed in any chemical or physical process.

law of conservation of mass (1.6) Mass can be neither created nor destroyed in any chemical or physical process.

law of constant composition (3.1) The composition of a compound is fixed; also called law of definite proportions.

law of definite proportions (3.1) The composition of a compound is fixed; also called law of constant composition.

law of multiple proportions (3.1) When two or more elements combine to form more than one compound, for a fixed mass of one element, the masses of the other element(s) in the compounds are in a small, whole-number ratio.

lead storage cell (16.5) A cell composed of a lead electrode in contact with lead(II) sulfate and a lead(IV) oxide electrode also in contact with lead(II) sulfate in an electrolyte of sulfuric acid.

LeChâtelier’s principle (17.3) When a stress is applied to a system at equilibrium, the equilibrium shifts so as to tend to reduce the stress.

length (2.2) The distance from one end of an object to the other.

light (4.1) In general, any electromagnetic radiation; specifically, visible light_the wave motion that affects the human eye.

light absorption (4.2) Process in which the energy of certain wavelengths of light is converted to energy of electrons in atoms, increasing their energy.

light emission (4.2) Process in which light of specific wavelengths is produced as electrons in atoms fall to lower energy levels.

limiting quantity (10.4) The quantity of the reactant that will be exhausted first in a chemical reaction, limiting the quantity of products that can be produced.

line formula (19.2) A formula for an organic compound that is written on a single line, such as CH3CH2COOH.

linear molecule (13.4) A molecule whose atoms all lie on a line.

liquid (12.1) A state of matter; a sample of matter that has a definite volume but assumes the shape of its container.

liter (2.2) The primary unit of volume of the metric system, equal to 1 dm3.

lobe (4.6) One portion of an atomic orbital.

lone pair (5.5) An unshared pair of electrons on a bonded atom.

macromolecule (5.5) A molecule containing hundreds of thousands to millions of covalently bonded atoms.

magnetic properties (4.7) The characteristics of substances that make them attracted to or repelled by magnetic fields.

magnetic quantum number (4.3) The quantum number (m) that designates the orientation in space of the volume occupied by an electron in an atom.

main group element (1.5) An element of one of the periodic groups labeled A, which extend up to the first or second period of the periodic table.

malleable (1.2) Capable of being pounded into various shapes.

mass (1.3) A fundamental characteristic of a sample of matter that quantifies its attraction to the earth (weight) and its resistance to a change in its motion (inertia).

mass number (3.3) The sum of the number of protons and the number of neutrons in an atom; the distinguishing difference among isotopes of a given element.

matter (1.3) Anything that has mass and occupies space.

melting (14.2) A change of phase from solid to liquid by heating.

metal (1.5) An element on the left in the periodic table, or a mixture of such elements.

metallic solid (14.1) A solid consisting of atoms of one or more elemental metals.

metalloid (1.5) An element near the dividing line between metals and nonmetals on the periodic table and that has properties of both metals and nonmetals.

metathesis reaction (8.3) A double displacement reaction.

meter (2.2) The primary unit of length in the metric system and SI.

metric system (2.2) A system of measurement whose units have subunits and multiples that are based on powers of 10.

metric ton (10.2) 1,000,000 grams.

mixture (1.1) A physical combination of substances that has an arbitrary composition and properties characteristic of its components.

molal (15.3) The unit of molality, abbreviated m.

molality (15.3) A measure of concentration defined as the number of moles of solute per kilogram of solvent; symbolized m.

molar (11.1) The unit of molarity; abbreviated M.

molar mass (7.3) The mass in grams of 1 mol of a substance.

molarity (11.1) A measure of concentration defined as the number of moles of solute per liter of solution; symbolized M.

mole (7.3) The chemical unit of quantity for any substance; equal to 6.02 3 1023 individual atoms, molecules, or formula units of the substance; abbreviated mol.

mole fraction (15.4) The ratio of the number of moles of a component (A) of a solution to the total number of moles in the solution; symbolized XA.

molecular formula (7.5) The formula of a molecular substance that gives the ratio of atoms of each element to the substance’s molecules.

molecular mass (7.1) The relative mass of a molecule of a substance compared to the mass of a 12C atom.

molecular shape (13.4) The spatial arrangement of the atoms in a molecule.

molecular solid (14.1) A solid consisting of (relatively small) molecules.

molecular weight (7.1) Molecular mass.

molecule (3.2, 5.5) An uncharged, covalently bonded group of atoms.

molten (8.3) Melted; in a liquid state without being dissolved.

monatomic ion (5.2) An ion consisting of one atom only.

monomer (19.4) A molecule that is capable of reacting with other similar molecules to form a polymer.

monosaccharide (19.5) A simple sugar, such as glucose, C6H12O6.

multiple bond (5.5) A double or triple bond.

n 1 , rule (4.4) The electron with the lower value for the sum of quantum numbers n and , is lower in energy.

natural logarithm (A.2) Logarithm to the base e.

net ionic equation (9.2) An ionic equation in which the ions that do not change (the spectator ions) are omitted.

network solid (14.1) A solid consisting of macromolecules.

neutral (3.3) Neither positively nor negatively charged.

neutral (8.4) Neither acidic nor basic.

neutralization reaction (8.4) A reaction of an acid and a base.

neutron (3.3) A subatomic particle that has no charge and a mass slightly greater than 1 amu.

noble gas (1.5) An element of periodic group 0±He, Ne, Ar, Kr, Xe, or Rn.

noble gas configuration (5.2) An electronic configuration like that of a noble gas, with eight electrons (or two for very light elements) in the outermost shell.

nomenclature (Chapter 6, Introduction) The systematic naming of chemical substances.

non-octet structure (5.5) Any electronic structure in which an atom in a molecule or ion contains more or fewer than eight electrons in its valence shell.

nonlinear molecule (13.4) See angular molecule.

nonmetal (1.5) Hydrogen or any element on the right of the stepped line in the periodic table.

nonpolar bond (13.3) A covalent bond in which the electrons are shared equally.

nonpolar molecule (13.5) A molecule in which the centers of positive and negative charge lie at the same place.

nonvolatile (15.5) Not easily vaporized.

normal (16.6) The unit of normality; symbolized N.

normal boiling point (14.2) The boiling point of a substance at a pressure of 1 atm.

normality (16.6) A measure of concentration equal to the number of equivalents of solute per liter of solution; symbolized N.

nuclear fission (20.3) The splitting of a nucleus into two more or less equal sized smaller nuclei, plus some subatomic particles.

nuclear fusion (20.4) Combination of nuclei in a nuclear reaction.

nuclear radiation (20.1) Alpha, beta, and/or gamma particles; particles emitted in nuclear reactions.

nucleus (3.3) The center of an atom, consisting of the protons and neutrons.

octet (5.2) A set of eight electrons in the outermost shell of an atom or ion.

octet rule (5.2) Atoms or ions with an octet are stable.

orbital (4.5) A part of a subshell of an atom having a given set of n, ,, and m quantum numbers.

orbital shape (4.6) The shape of the volume of space that can be occupied by an electron in an atom.

organic acid (19.3) An organic compound containing the ±COOH functional group.

organic chemistry (Chapter 1, Introduction) The branch of chemistry dealing with organic compounds.

organic compound (Chapter 19, Introduction) A compound containing at least one carbon-carbon or carbon-hydrogen bond.

organic halide (19.3) An organic compound that has at least one halogen atom per molecule.

osmotic pressure (15.5) The difference in pressure between a solution and the pure solvent separated by a semipermeable membrane.

outermost shell (5.2) The highest shell that contains electrons.

overall equation See total equation.

oxidation (16.4) An increase in oxidation number.

oxidation number (16.1) The difference in the number of electrons in a neutral atom and the number "controlled" by the atom in a compound, where control is assigned to the more electronegative atom of a covalent bond.

oxidation-reduction reaction (16.4) A reaction in which the oxidation number of one element is raised and the oxidation number of another element (or the same element) is lowered.

oxidation state (16.1) The oxidation number.

oxidizing agent (16.4) A species that can increase the oxidation number of another reactant.

oxoacid (6.3) An acid containing oxygen.

oxoanion (6.2) An anion containing oxygen covalently bonded to another element.

ozone (5.5) O3, an allotrope of oxygen.

parent isotope (20.1) The isotope that is the reactant in natural radioactive decay.

partial pressure (12.9) The pressure of one gas in a mixture of gases.

Pauli exclusion principle (4.3) The rule that prohibits more than one electron in an atom from having the same set of four quantum numbers.

percent (2.1, 3.1, A.1) Parts per hundred parts.

percent composition (7.2) The percentages by mass of all elements in a compound.

percent yield (10.5) The ratio of actual yield to theoretical yield, expressed as a percentage.

perfectly elastic collision (12.10) A collision that occurs with no loss of kinetic energy.

period (1.5) One of the seven horizontal rows of the periodic table.

periodic table (1.5) An assemblage of elements in order of atomic number, with elements having similar chemical properties aligned in vertical columns.

periodicity of electronic configuration (4.8) The regularity of the change in the outermost electronic configuration of the elements in the groups of the periodic table.

peroxide ion (6.2) The O222 ion.

pH (18.3) A measure of the acidity of a solution, defined as 2log [H3O1].

phase (12.1) A state of matter_solid, liquid, or gas.

phase change (14.2) A transition from one to another of the three states of matter_for example, from gas to liquid.

photon (4.1) A particle of light.

physical change (1.1) A process in which no change in composition occurs.

physical chemistry (Chapter 1, Introduction) The branch of chemistry dealing with the properties of substances.

physical equilibrium (14.2) A situation in which two exactly opposite physical processes are occurring at the same rate in the same system.

pipet (11.3) A piece of laboratory glassware designed to deliver an exact volume of liquid.

polar bond (13.3) A covalent bond in which there is unequal sharing of electrons.

polar molecule (13.5) A molecule that has a permanent dipole.

polyatomic ion (5.5) An ion composed of two or more atoms.

polymer (19.4) A molecule built from many (thousands or even more) smaller molecules (monomers) or parts of molecules.

polysaccharide (19.5) A complex carbohydrate composed of more than one monosaccharide.

positron (20.3) A subatomic particle created in a nuclear reaction that has the same properties as an electron, except for being positively charged.

postulate (3.2) A proposed explanation for an observation or set of observations.

precipitate (8.3) A solid formed from substances in solution.

precision (2.3) The degree of reproducibility of measurements.

prefix (6.1) A word fragment placed before another part of a word to impart a special meaning.

pressure (12.1) Force divided by area.

principal quantum number (4.3) The main quantum number (n) of an electron in an atom, which is the major factor determining the energy of the electron and its mean distance from the nucleus.

proceed to the left (17.2) A phrase used to indicate that the products of a chemical equation (as written) will yield the reactants.

proceed to the right (17.2) A phrase used to indicate that the reactants of a chemical equation (as written) will yield the products.

product (8.1) Any substance produced in a reaction and appearing on the right-hand side of a chemical equation.

property (1.2) A characteristic of a substance.

proportion (3.1, A.1) The ratio of number of a certain item divided by the total number of items. (Compare to percent.)

propylene (19.1) Propene, CH2œCHCH3.

protein (19.4) A polymer formed from amino acids.

proton (3.3) A subatomic particle with a mass slightly greater than 1 amu and a charge of 11.

proton (18.1) In the Brønsted sense, the nucleus of the hydrogen atom.

proton acceptor (18.1) A molecule or ion that accepts a proton; a Brønsted base.

proton donor (18.1) A molecule or ion that donates a proton; a Brønsted acid.

pure substance (1.1) An element or compound.

quantitative property (1.2) A property that is measurable.

quantum numbers (4.3) Four numbers assigned to each electron in an atom that describe the energy and other properties of the electron.

radiation See electromagnetic radiation or nuclear radiation.

radical (19.3) The hydrocarbon portion of an organic molecule that has a functional group.

radioactive dating (20.2) The determination of the age of an object from the measurement of the radioactivity of an isotope it contains.

radioactive decay (20.1) Disintegration of nuclei of an isotope.

radioactive series (20.1) A parent isotope and the successive daughters of its natural decay.

radioactivity (20.1) Spontaneous reaction of nuclei.

random motion (12.10) Motion of molecules in arbitrary directions.

Raoult’s law (15.5) The vapor pressure of a solute in a solution is equal to its mole fraction in the solution times the vapor pressure of the pure solute: PA 5 XAPoA.

rate (17.1) The number of moles per liter produced or used up in a chemical reaction per unit time.

reactant (8.1) Any substance that undergoes a reaction and thus appears on the left-hand side of a chemical equation.

reacting ratio (10.1) A ratio of coefficients from a balanced equation, which represents the ratio of moles of reactants and/or products involved in the reaction.

reaction See chemical reaction.

reactive (8.3) Having a high tendency to undergo chemical reaction.

reagent (8.1) A reactant.

redox reaction (16.4) An abbreviation for oxidation-reduction reaction.

reducing agent (16.4) A species that reduces the oxidation number of another reactant.

reduction (16.4) The lowering of oxidation number.

relative scale (3.4) A scale based on an arbitrarily chosen standard; the atomic mass scale is a relative scale of masses based on the mass of 12C.

rounding (2.3) Reducing the number of digits in a calculated result to the proper number of significant digits.

salt (6.3, 8.4) An ionic compound that does not contain H1, OH2, or O22 ions.

salt bridge (16.5) A solution of an inert electrolyte that connects two half cells in order to complete the circuit in a voltaic cell.

saturated fat (19.5) A fat that contains no carbon-carbon multiple bonds.

saturated hydrocarbon (19.1) A compound containing only carbon and hydrogen linked only by single bonds.

saturated solution (15.2) A solution that holds as much solute as it is capable of holding stably at a given temperature.

scientific method (1.6) The method employed by scientists consisting of (1) collection of data by observation and experimentation; (2) generalization of much data into a statement, known as a law; (3) proposal of an explanation for the law, called a hypothesis; and (4) acceptance of the hypothesis as a theory if the hypothesis can be substantiated by all additional experiments.

scientific notation (2.4) A format for writing large and small numbers, using a coefficient with one (nonzero) integer digit times 10 to an integral exponent.

second (2.6) The primary unit of time in SI.

second ionization energy (13.2) The energy required to remove an electron from a gaseous, monopositive ion to form a gaseous, dipositive ion.

shell (4.2) A set of energy levels for electrons in an atom that is characterized by a given value of the principal quantum number, n.

shift (17.3) A net reaction of a system at equilibrium in response to a stress_a change in the conditions on the system.

SI (2.2) Système International d’Unités; the modern form of the metric system.

significant digit (2.3) Any digit that reflects the accuracy with which a measurement was made.

significant figure (2.3) A significant digit.

single bond (5.5) A covalent bond formed by a single pair of shared electrons.

single displacement reaction (8.3) The reaction of an element with a compound to produce another element and another compound.

single substitution reaction (8.3) A reaction in which an uncombined element reacts with a compound to produce a new compound and a different uncombined element.

soap (19.5) A salt of a fatty acid, such as sodium stearate, Na1C17H35COO2.

sodium chloride structure (5.2) The three-dimensional lattice containing alternating positive and negative ions that is characteristic of sodium chloride and many other ionic compounds.

solid (12.1) A state of matter; a sample of matter that has a definite shape and volume.

solubility (8.3, 15.2) The concentration of a saturated solution at a given temperature.

solute (11.1) The component of a solution that is dissolved in another component—the solvent.

solution (1.1) A homogeneous mixture.

solvent (11.1) The component of a solution that does the dissolving.

specific heat (14.3) The quantity of heat required to raise the temperature of 1 g of a substance by 18C; the specific heat capacity, symbolized c.

spectator ion (9.2) An ion that is present but does not change during a chemical reaction.

spin quantum number (4.3) The quantum number (s) that determines electron pairings.

stability (8.3) Resistance to reaction; relative lack of reactivity.

standard (2.2) A basis for comparison, such as the mass of 12C.

standard atmosphere (12.1) A pressure of 760 torr.

standard exponential form (2.4) A format in which a number is expressed as a coefficient with one (nonzero) integer digit times 10 to an integral exponent.

standard state (14.4) The normal state for a substance at 1 atm and the temperature involved; for example, the standard state for oxygen at 258C is gaseous O2 molecules.

standard temperature and pressure (12.4) 08C and 1 atm, abbreviated STP; used in gas law problems.

state (8.2, 12.1) A phase in which matter exists—solid, liquid, or gas.

state function (14.4) A variable that depends only on the initial and final states of a system and not on the path between them.

state of a system (12.2) The condition of a system.

state of subdivision (17.1) The particle size of a sample of a solid.

Stock system (6.2, 16.2) The nomenclature system for inorganic compounds in which the oxidation state (or charge for a monatomic cation) is represented as a Roman numeral in the name of the compound.

stoichiometry (10.1) The determination of how much a reactant can produce or how much of a product can be produced from a given quantity of another substance in a reaction.

stress (17.3) Any change in conditions affecting a system at equilibrium.

strong acid (8.3) An acid that reacts completely with water to form ions in solution.

strong base (8.3) A base that is fully ionized in water solution.

structural formula (5.5) A formula in which lines represent electron pairs shared by covalently bonded atoms.

subatomic particle (3.3) A proton, neutron, electron, deuteron, positron, alpha particle, etc.

sublimation (13.6) A phase change in which a solid goes directly into the gas phase.

subscript (5.1) A number following the symbol of an element (or a closing parenthesis) that denotes the number of atoms of the element (or the number of groups) in the formula unit.

subshell (4.5) The portion of a shell characterized by the same principal quantum number and the same angular momentum quantum number.

substance See pure substance.

sugar (19.5) A carbohydrate consisting of a monosaccharide or a combination of them—for example, sucrose.

superoxide ion (16.1) The O22 ion.

supersaturated solution (15.2) A solution holding more solute than it can hold stably at a given temperature.

surroundings (12.2) Anything outside of the system under investigation.

symbol (1.4) A one- or two-letter representation of an element.

synthetic fiber (19.4) A polymer, such as nylon, that has the form of a fiber.

system (12.2) The portion of the universe under investigation.

Système International d’Unités See SI.

temperature (2.6) The intensity of heat in a body.

ternary compound (8.3) A compound consisting of three elements.

tetrahedral molecule (13.4) A molecule with bonded atoms oriented toward the corners of a tetrahedron (a solid object with four sides, all of which are identical equilateral triangles).

theoretical yield (10.5) The calculated quantity of product that would result from a chemical reaction based on the laws of stoichiometry.

theory (1.6) A generally accepted explanation for a law (or series of observations).

third ionization energy (13.2) The energy required to remove an electron from a gaseous, dipositive ion to form a gaseous, tripositive ion.

titration (11.3) An experimental technique used to determine the concentration of a solution of unknown concentration or the number of moles in an unknown sample of a substance.

torr (12.1) A unit of pressure equal to 1 mm Hg or atm.

total bond order (19.3) The number of electron pairs shared by an atom in a molecule or ion.

total equation (9.2) The equation representing the complete compounds undergoing reaction, as opposed to an ionic or a net ionic equation.

tracer (20.1) A radioactive isotope of an element used to determine what happens to the element, often in some biochemical system.

transition element (1.5) Any element in the groups that start in the fourth period of the periodic table, having atomic numbers 21–30, 39–48, 57, 72–80, or 104 or higher.

transmutation (20.3) The conversion of one element into another by a nuclear reaction.

trigonal planar molecule (13.4) A molecule with atoms oriented toward the corners of an equilateral triangle, with the central atom in the same plane.

trigonal pyramidal molecule (13.4) A molecule with atoms oriented toward the corners of an equilateral triangle, with the central atom out of that plane.

triple bond (5.5) A covalent bond consisting of three pairs of electrons shared between two atoms.

tritium (20.4) The isotope 3H.

uncertainty principle See Heisenberg uncertainty principle.

unit (2.1) A standard division of measure having a certain value; for example, the meter is the primary metric unit of length.

unsaturated fat (19.5) A fat that contains one or more carbon-carbon multiple bonds per molecule.

unsaturated hydrocarbon (19.1) A compound containing only carbon and hydrogen and having one or more multiple bonds per molecule.

unsaturated solution (15.2) A solution that contains less solute than it could hold stably at a given temperature.

unshared pair (5.5) A pair of electrons in a molecule or ion that is not shared between atoms.

urea (Chapter 19, Introduction) NH2CONH2 (an organic compound despite its lack of carbon-carbon or carbon-hydrogen bonds).

valence electron (5.2) An electron in or from the outermost electron-containing shell of an uncombined atom.

valence shell (5.2) The outermost shell containing electrons in an uncombined atom, or that same shell even when the atom is combined in a compound.

van der Waals force (13.6) An intermolecular force resulting from instantaneous dissymmetry of charge in otherwise nonpolar molecules.

vapor (14.2) A gas in contact with its liquid (or solid) phase.

vapor pressure (12.9, 14.2) The pressure of the vapor in equilibrium with its liquid (or solid).

vapor-pressure lowering (15.5) A decrease in the vapor pressure of a solvent due to the presence of a solute.

vaporization (14.2) A phase change from liquid to gas (vapor).

volatile (15.5) Easily vaporized.

voltaic cell (16.5) An apparatus that provides a combination of half reactions that can produce an electric current.

volume (2.2) The extent of space occupied by a sample of matter.

volume ratio (12.8) The ratio of volumes of gases involved in a chemical reaction.

water ionization constant (18.3) The equilibrium constant for the autoionization of water; symbolized Kw; at 258C, Kw 5 [H3O1][OH2] 5 1.0 3 10214.

wavelength (4.1) The length of a single wave.

weak acid (8.3) An acid that reacts only partially with water to form ions.

weak base (8.3) A base that reacts only partially with water to form ions.

weighted average (3.4) The average value of several types of items, taking into account the number of individual items of each type.

work (14.4) All forms of energy except heat.