APPENDIX 5

Glossary

Absolute Zero	The lowest achievable temperature of 0 Kelvin or −273°C.
Accuracy	How close data come to the accepted or “real” value.
Actinides	Elements with the atomic numbers 90 through 103.
Activation Energy	The energy needed to start a reaction.
Alcohols	Organic compounds that have the function group R—OH.
Alkali Metals	Group 1 metals of the periodic table.
Alkaline Earth Metals	Group 2 metals of the periodic table.
Alkanes	Saturated hydrocarbons that contain all single bonds.
Alkenes	Unsaturated hydrocarbons that have a double bond between two carbons.
Alkyl Halides	Class of organic compounds in which a halogen is bonded to the organic molecule.
Alkynes	Unsaturated hydrocarbons that have a triple bond between two carbons.
Allotropes	Different substances in the same phase formed from the same elements.
Alpha Particles	Particles containing two protons and two neutrons. These particles are identical to helium-4 nuclei. The symbols are 42He or α.
Amides	Organic compounds that have the function group R—CO—NH2.
Amines	Organic compounds that have the function group R—NH2.
Amphoteric	Describes a substance that can act as either an acid or a base.
Anion	A negatively charged ion.
Anode	Electrode where oxidation occurs.
Artificial Transmutation	A nuclear reaction in which an isotope is being bombarded with a particle to trigger the transmutation.
Atom	Composed of protons, neutrons, and electrons, an atom is a particle that defines an element.
Atomic Mass	The atomic mass takes into account all the masses of the isotopes of an atom and their relative abundance.
Atomic Number	Number of protons located in the nucleus of an atom. Can also be defined as the nuclear charge of an atom.
Atomic Radius	The distance from the atom’s nucleus to the outermost electron of that atom.
Atomic Theory	Theory of the atom as stated by John Dalton: All matter is composed of atoms; all atoms of a given atom are alike; compounds are made up of atoms combining in fixed proportions; a chemical reaction involves the rearrangement of atoms; and atoms are neither created nor destroyed in a chemical reaction.
Avogadro’s Number	One mole, or 6.02 × 1023.
Beta Particle	An electron that is ejected from the atom’s nucleus.
Binary Compounds	Compounds that have only two different elements present.
Boiling Point	The point at which the vapor pressure of a liquid is equal to the surrounding/atmospheric pressure.
Boyle’s Law	A gas law stating that at constant temperature, pressure and volume have an inverse relationship.
Buffer	A solution that is resistant to changes in pH.
Calorie	A measure of heat energy; 1 calorie is equal to 4.18 joules.
Carbonyl Group	Part of an organic compound characterized by the double bond between a carbon atom and an oxygen atom, C=O.
Cathode	Electrode that is the site of reduction.
Cation	An ion with a positive charge.
Celsius	A measure of temperature in which the freezing point of water is 0°C and the boiling point of water is 100°C.
Chain Reaction	Reaction in which one event causes multiple events to occur until all materials have been consumed.
Charles’ Law	A gas law stating that at constant pressure, temperature and volume are directly proportional.
Chemical Formulas	An expression of the composition of a compound by a combination of symbols and figures that show which elements are present and how much of each element is in a compound.
Chemical Properties	Properties that are observed with regard to how a substance reacts with other substances.
Coefficient	Numerical indication of the quantity of a substance in an equation.
Colligative Properties	The properties of a solvent that depend on the concentration of dissolved particles present.
Combined Gas Law	A gas law that combines the laws of Charles and Boyle.
Common Ion Effect	A decrease in the solubility of a salt due to the shift in equilibrium when an ion is added to the solution.
Compound	Two or more elements combined with definite proportions.
Conjugate Acid	The acid formed when a Brønsted-Lowry base gains a proton.
Conjugate Base	The base formed when a Brønsted-Lowry acid loses a proton.
Conjugate Pair	An acid or base that differs only in the presence or absence of a proton.
Conservation of Charge	The sum of the charges of the reactants will be equal to the sum of the products.
Coordinate Covalent Bond	A covalent bond in which one atom donates both electrons.
Covalent Bond	A bond formed when two nonmetal atoms share electrons in order to satisfy their need to have a full outermost principal energy level.
Dalton’s Law of Partial Pressures	A law stating that the combined pressure of a combination of gases is equal to the sum of the individual pressures of the gases.
Decay Series	Series of decays an isotope will undergo until a stable isotope is formed.
Decomposition	The process by which one compound breaks down into many substances.
Density	Mass per unit of volume.
Deposition	Changing from the gas phase to the liquid phase without any apparent solid phase in between.
Dipole	The condition in which a molecule has a “buildup” of negative charge on one side and a positive charge on another side.
Dispersion Forces	Weak forces existing between nonpopular molecules. Also known as Van der Waals forces.
Double Bond	A covalent bond that involves the sharing of two pairs of electrons.
Double Replacement	Reaction in which two elements exchange anions and cations to form the products.
Ductile	Has the ability to be rolled into thin wires.
Electrode Potentials	Voltage of a given oxidation or reduction half reaction.
Electrodes	Sites for oxidation and reduction.
Electrolysis	A reaction in which electricity is used to make a nonspontaneous reaction occur.
Electrolyte	A solute that creates ions in solution that can carry an electrical current.
Electrolytic Cell	A device that requires an outside source of current to make a nonspontaneous reaction occur.
Electron	A negatively charged particle that orbits the nucleus of an atom in the principal energy levels.
Electronegativity	A measure of an atom’s ability to attract electrons.
Electroplating	Coating a substance with a metal.
Element	A substance that is unable to be broken down chemically.
Empirical Formula	Shows the lowest ratio of all the elements of a compound to each other.
End Point	Point of a titration where the indicator changes color.
Endothermic	When more energy is absorbed than released in a chemical reaction.
Energy	The ability to do work.
Enthalpy	The heat absorbed or released in a chemical reaction. Also known as the heat of reaction.
Entropy	Used to describe chaos, randomness, and disorder.
Equilibrium	A state of balance between two opposing reactions that are occurring at the same rate.
Ethers	Organic compounds that have the functional group R—O—R.
Excess Reagent	The compound that does not completely react in a chemical reaction.
Excited State	The movement of electrons to a higher energy level once energy has been added to an atom.
Exothermic	Describing a chemical reaction in which more energy is released than absorbed.
Families	The vertical columns on the periodic table.
Faraday	The charge of one mole of electrons. A charge of approximately 96,500 coulombs.
Filtrate	The aqueous portion of a sample that has been poured through filter paper.
Fission	The splitting of larger nuclei into smaller ones, causing a release of nuclear energy.
Freezing	The process by which particles of the liquid phase enter the solid phase.
Functional Groups	Particular arrangement of atoms in organic compounds.
Fusion	The joining of smaller nuclei to form a larger one, causing a release of nuclear energy.
Gamma Rays	High-energy electromagnetic radiation emitted from the nucleus of a radioactive atom.
Gas	A phase of matter characterized as having no definite volume or shape and having molecules spaced far apart.
Geiger Counter	A device used to detect and measure the activity of radioactive particles.
Gibbs Free Energy	Equation used to determine if a reaction will be spontaneous.
Graham’s Law	At the same temperature and pressure, gases effuse at a rate inversely proportional to the square roots of their molecular masses.
Ground State	When the electrons are in their lowest energy state.
Group	Vertical column on the periodic table.
Half Cell	Part of a voltaic cell where oxidation or reduction can occur.
Half-Life	The amount of time it takes for half a radioactive substance to decay.
Half Reactions	Two separate reactions that show the oxidation and reduction reactions separately.
Halogens	Elements found in group 17 of the periodic table.
Heat of Reaction	The heat absorbed or released in a chemical reaction. Also known as enthalpy.
Hess’s Law	The sum of the heats of reaction of the steps in a reaction is equal to the overall heat of reaction.
Heterogeneous	Describing a mixture that is not the same throughout.
Homogeneous	Describing a mixture that is the same throughout.
Hund’s Rule	Electrons will fill an orbital singly to the maximum extent possible before pairing up.
Hybridization	The promotion of an electron to a higher energy level so that the atom can bond to another atom.
Hydrocarbon	An organic compound that consists of only the elements hydrogen and carbon.
Hydrogen Bonding	A weak force that comes about when hydrogen is bonded to fluorine, oxygen, or nitrogen.
Hydrolysis	The addition of water to a salt to form the acid and base from which the salt was made.
Ideal Gas Law	A law that states that an ideal gas obeys the equation PV = nRT.
Indictors	Substances that change color to indicate if a substance is acidic or basic.
Intermolecular Bond	A bond that exists between molecules.
Intramolecular Bond	A bond that exists between atoms.
Ion	An atom that has gained or lost electrons.
Ionic Bonds	Very strong bonds that are formed between a cation and an anion.
Ionization Energy	The energy needed to remove an electron from an atom to form an ion.
Isomers	Compounds with the same molecular formula but different structures.
Isotopes	Atoms that have the same atomic number but a different mass number due to having a different number of neutrons.
Joule	A measure of heat energy. 4.18 Joules is equal to 1.0 calories.
Kelvin	The Kelvin scale is based upon the lowest temperature that can be achieved, 0 K (absolute zero) or −273°C.
Kinetic Energy	Energy that is in motion.
Kinetic Molecular Theory	Set of rules that are assumed to govern the motion of molecules.
Lanthanides	Elements with the atomic numbers 58 through 71.
Lattice	Regular structure among the atoms in a solid.
Law of Conservation of Mass	The law stating that mass cannot be created or destroyed in a chemical reaction.
Le Châtelier’s Principle	When a stress or change in conditions is applied to a system at equilibrium, the point of equilibrium will shift in such a manner as to relieve the applied stress.
Lewis Structure	A drawing of the structure of a compound in which the arrangement of the valence electrons is represented by the use of dots.
Limiting Reagent	Substance that is completely used up in a chemical reaction.
Line Spectrum	Specific wavelengths of light emitted from an atom when the electrons return to the ground state from the excited state.
Liquids	Have a definite volume, take the shape of the container they are placed in, and have touching molecules.
Litmus	Indicator that turns red in acid and blue in base.
Malleable	Has the ability to be hammered into thin sheets.
Mass	Measure of the quantity of particles in an object.
Mass Action Equation	An equation written that shows the product of the concentrations of the products raised to the power of their coefficients divided by the product of the concentrations of the reactants raised to the power of their coefficients is equal to a constant.
Mass Defect	The amount of mass of the particles involved in the nuclear reaction that is converted to energy.
Mass Number	The total number of nucleons (protons and neutrons) found in an atom.
Matter	Anything that has mass and takes up space.
Melting	Particles of the solid phase entering the liquid phase.
Melting Point	The temperature at which the particles of the solid phase enter the liquid phase.
Meniscus	The curvature of a liquid that is the result of the adhesive forces between the liquid’s molecules and the walls of a glass container.
Metallic Bond	A bond in which the electrons are free to move among the metal atoms.
Metalloids	Elements that exhibit some of the properties of metals and nonmetals.
Metals	Elements that are characterized by the ability to conduct heat and electricity, have a shiny luster, and lose electrons in a chemical reaction.
Mixtures	The result of combinations of elements and/or compounds.
Molality	Way of expressing concentration. Ratio of moles of solute to kilograms of solvent.
Molar Volume	Volume (22.4 liters) that one mole of a gas will occupy at STP.
Molarity	Way of expressing concentration. The ratio of moles of solute to total liters of solution.
Mole	A unit of Avogadro’s number. A mole of particles is equal to 6.02 × 1023 of those particles.
Mole Ratio	The ratio of the number of moles of one substance to the moles of another substance as dictated by the balanced equation.
Molecular Formulas	Indicate the total number of atoms of each element that are present in a covalently bonded molecule.
Molecule-Ion Attraction	Attraction between charged ions and polar molecules in a solution.
Natural Transmutation	Transmutation that does not need to be triggered by a particle bombarding the isotope.
Network Solid	Nonmetal atoms bonding to each other in a covalent fashion to form a continuous network.
Neutralization	The process in which an acid and a base react to form salt and water.
Neutron	A particle with no charge that is found in the nucleus of an atom.
Noble (Inert) Gases	Gases found in group 18 of the periodic table.
Nonmetals	Elements that are characterized by being poor conductors of heat and electricity, being soft and brittle, and tending to gain electrons to form anions.
Nonpolar Covalent Bond	A covalent bond in which the electrons are shared and distributed equally.
Nucleons	Particles found in the nucleus of an atom (protons and neutrons).
Octet Rule	An atom will desire eight electrons in its outermost principal energy level to maximize its stability.
Orbital	Region around the atom where electrons are most likely to be found.
Organic Chemistry	Study of carbon and carbon-containing compounds.
Oxidation	A loss of electrons.
Oxidation Number	The charge on an ion or the charge that an atom “feels.”
Oxidizing Agent	The reducing substance that causes the oxidation of other substances.
Pauli Exclusion Principle	A rule that states there cannot be more than two electrons in an atomic orbital. It also states that no two electrons can have the same four quantum numbers.
Percent Composition	Ratio of the total mass of an element in a compound to the total mass of the compound.
Period	Horizontal row on the periodic table.
pH	Negative logarithm of the hydrogen ion concentration of a solution.
Phenolphthalein	Indicator that is colorless in acid, and pink (or purple, magenta) in base.
Physical Properties	Observable and measurable properties of a substance.
Pi Bond	The second or third bond that is formed between hybridized atoms that have orbitals which overlap.
Polar Covalent Bond	A covalent bond that involves electrons not being shared equally.
Polyatomic Ions	Ions that have many atoms in them.
Positron	A particle that has the same mass as an electron but a charge of 1+.
Potential Energy	Energy that is stored.
Precipitate	An insoluble substance that separates from, and forms in, a solution.
Precision	How closely results from the same experiment agree with one another.
Pressure	The measurement of the ratio of the force exerted on an area.
Products	The results of a chemical reaction.
Proton	A particle found in the nucleus of an atom with a positive charge.
Quarks	Subatomic particles that make up protons and neutrons. Quarks have charges of +2/3 or −1/3.
Rate	Change in concentration over time.
Reactant	A substance used at the start of an equation.
Redox	Another term for oxidation and reduction.
Reducing Agent	The oxidized substance causing the reduction of other substances.
Reduction	A gain of electrons.
Residue	The solids that are trapped by filter paper.
Reversible Reaction	A reaction in which products formed further react to form the original reactants.
Rows	Horizontal rows on the periodic table.
Salt Bridge	An apparatus that allows ions to migrate from one half cell to another.
Saturated	Describing a solution in which a dissolved solute and an undissolved solute are in equilibrium.
Semimetals	Elements that exhibit some of the properties of metals and nonmetals.
Sigma Bond	A bond that arises from the overlap of two s orbitals or from the overlap of one s and one p orbital.
Single Replacement	Reaction where one element replaces another element.
Solids	Substances that have definite shape and volume. The atoms are in a rigid, fixed, regular geometric pattern.
Solubility	The ability of a substance to dissolve in another substance.
Solubility Product Constant	The equilibrium constant of a slightly soluble salt.
Solute	A substance that is dissolved into a solvent.
Solution	A homogenous mixture of a solute and a solvent.
Solvent	A substance that a solute is dissolved into.
Spectators	Substances that do not take part in a reaction.
Spontaneous	A process that occurs without added external energy or without additional intervention.
Standard Pressure	Pressure characterized by pressures equal to 760 mm Hg, 760 torr, 101.3 kPa, or 1.0 atm.
Standard Temperature and Pressure	A common standard of conditions, defined as 0°C and 1 atm (273 K and 760 torr).
Stock Method	Method for naming compounds where a roman numeral is used to indicate the amount of positive charge on the cation.
Stoichiometry	The branch of chemistry that deals with the amounts of products produced from certain amounts of reactants.
Sublimation	Changing from the solid phase to the gas phase without any apparent liquid phase in-between.
Substance	A variety of matter with identical properties and composition.
Supersaturated	When a solution contains more solute than a saturated solution would at a given temperature.
Symbol	Letter(s) designation for an element.
Synthesis	When many substances come together to form one compound.
Temperature	Average kinetic energy possessed by a sample.
Titration	The process by which acids and bases can be measured out in exact quantities so that they neutralize each other exactly and without any excess.
Transition Metals	Metals found in groups 3 through 10 of the periodic table.
Transmutation	Formation of a new element when an element undergoes nuclear disintegration.
Triple Bond	A covalent bond that involves the sharing of three pairs of electrons.
Triple Point	A specific point in temperature and pressure at which solid, liquid, and gas exist at the same time.
Unsaturated	Describing a solution that contains less solute than a saturated solution would at a given temperature.
Valence Electrons	The electrons that are located in the outermost principal energy level.
Van der Waals Forces	Weak forces existing between nonpolar molecules. Also known as dispersion forces.
Vapor Pressure	Pressure exerted by the vapor of a liquid as the molecules of the liquid evaporate.
Vaporization	Process by which a liquid enters the gas phase.
Voltaic Cell	A setup that allows a redox reaction to occur spontaneously so that the electrons can be used to do work.
Volume	The space an object occupies.