| Term | Definition |
| acid | substance that forms hydronium ions with water or donates a proton |
| activation energy | the initial energy necessary for a reaction to start |
| alkali metals | the family of Li, Na, K, Rb, Cs |
| alkaline earth metals | the family of Be, Mg, Ca, Ba, Ra |
| NH3 | ammonia |
| amphoteric | reacts like an acid or a base |
| atom | the fundamental building block of matter |
| atomic mass | the exact mass of an atom |
| atomic number | the number of protons an element has |
| Avogadro's number | the number of particles in one mole of a substance 6.02 x 10^23 |
| balanced equation | chemical equation with equal numbers of each element on both sides |
| barometric pressure | the pressure of the atmosphere at a specific location |
| base | a substance that forms OH in water or a proton acceptor |
| buffers | a substance that resists the change in pH |
| catalyst | a substance that speeds up a reaction without being altered itself |
| chemical change | the change in composition and properties of a substance in a reaction |
| chemical equation | the statement showing how substances react using chemical formulas |
| chemical equilibrium | the condition when substances exchange position at equal rates |
| chemical formula | the symbols and subscripts showing the composition of a compound |
| chemical properties | characteristics describing how a substance reacts with other substances |
| chemistry | the study of the structure of matter, its properties, and composition |
| coefficients | the numbers in front of chemical formulas showing the formula units |
| P1V1/T1 = P2V2/T2 | combined gas law |
| compound | two or more elements bonded together through a chemical reaction |
| concentrated solution | a solution that is almost saturated |
| concentration of a solution | the number of moles per unit volume |
| condensation | changing phase from a gas to a liquid |
| conjugate pair | an acid and a base that may be formed reversibly from one another |
| conservation of charge | the number of + and - charges before a reaction = the number afterwards |
| covalent bond | a chemical bond where atoms share electrons |
| crystal lattice | the chemical structure of atoms in a crystal |
| Dalton's Law | a mixture of gasses: the total pressure = the sum of individual pressures |
| decomposition reaction | reaction where a substance breaks down into its individual components |
| density | the mass divided by the volume |
| diatomic | two atoms bonded together |
| dilute solution | a weak solution not close to the saturation point |
| dissociation | a substance separates in water to form an acid or a base |
| double replacement reaction | a reaction when two + ions switch position in a chemical reaction |
| electrolytes | substances that dissociate forming solutions that conduct electricity |
| electron | the subatomic particle that orbits the nucleus and has a - charge |
| electron configuration | the arrangement of electrons about the nucleus |
| electrovalent bonds | ionic bonds, two substances exchange electrons to form a chemical bond |
| element | the smallest unit of matter that retains its properties |
| empirical formula | the formula showing the composition in the simplest ratio of elements |
| endothermic reaction | a reaction that absorbs energy |
| energy | the ability to do work |
| energy levels | the shells with distinct energies where electrons are located |
| enthalpy | the heat energy gained or lost during a chemical reaction |
| entropy | a measure of the randomness of a reaction |
| equilibrium constant ke | the value of the mass action expression when the reaction is at equilibrium |
| equilibrium vapor pressure | the pressure where a vapor is in equilibrium with the liquid |
| evaporation | the change of phase where a liquid changes to a gas |
| exothermic reaction | a reaction that gives off energy |
| family | a vertical column of elements on the periodic table |
| filtration | the process of separating a precipitate from the solution |
| fluorine | the most reactive nonmetal |
| filtration | the temperature where a liquid changes phase to a solid |
| gram | a mass unit |
| gram atomic mass | the atomic mass of a substance in grams = AMU |
| gram formula mass | the mass of a chemical formula in grams |
| group | a vertical column of elements on the periodic table |
| halogens | the family of F, Cl, Br, I, At |
| HCl (aq) | hydrochloric acid |
| heat of fusion | the heat energy needed to change a liquid to a solid |
| heat of vaporization | the heat energy needed to change a liquid to a gas |
| heterogeneous mixture | a mixture with uneven distribution of solutes and solvent |
| homogeneous mixture | a mixture with uniform distribution of solutes and solvent |
| hydrated ions | ions surrounded by water molecules |
| H | hydrogen atom |
| H+ | hydrogen ion |
| H2 | hydrogen molecule |
| hydrolysis | a chemical reaction where water is a reactant |
| hydronium ion | a water molecule with an extra hydrogen ion attached |
| hydroxide | OH- |
| ideal gas equation | PV=nRT |
| ionic compound | a compound that has a charge |
| ionization | the process that forms an ion |
| ions | positively or negatively charges substances |
| Iron III | an iron atom missing three electrons |
| isotopes | an element with additional or missing neutrons |
| joule | the unit of energy in the SI system |
| Kelvin | temperature unit |
| kinetic theory | matter possesses internal energy and particles are constantly in motion |
| La Chatelier's principle | a reaction in equilibrium will adjust concentrations to counter stresses |
| limiting reactant | the reactant that is completely used up in a reaction |
| Lithium | the most reactive metal |
| mass | the measure of a quantity of matter |
| matter | anything that has mass and takes up space |
| melting point | the temperature where a solid changes phase to a liquid |
| metal | an element that loses electrons easily in a chemical reaction |
| milliliter | a volume unit |
| mixture | substances associated together that are not chemically combined |
| molarity | a measure of the concentration defined as M = moles / total volume |
| mole | the mass of the sample divided by the gram formula mass |
| molecular formula | the chemical formula showing the number of atoms in a molecule |
| molecule | a covalently bonded substance |
| neutralization | the reaction of an acid and a base forming salt and water |
| neutron | the subatomic particle in the nucleus of an atom with no charge |
| nitrogen family | the group of elements headed by nitrogen |
| noble gases | the gases of group 18 that do not readily react with other substances |
| nonmetal | elements on the right side of the periodic table that tend to gain electrons |
| nucleon | the proton and neutron combination |
| nucleus | the central part of an atom containing the nucleons |
| orbitals | the paths that electrons occupy as they travel around the nucleus |
| oxidation | an element loses electrons |
| O^2- | oxide ion |
| oxygen family | the groups of elements headed by oxygen |
| O2 | oxygen molecule |
| pascal | the SI unit of pressure |
| percent error | (actual - experimental / actual) x 100 |
| period | a horizontal row of elements on the periodic table |
| periodic table | the chart summarizing the characteristics of the elements |
| pH | concentration of H+ in a solution |
| phases | solid, liquid, and gaseous states of matter |
| polar | when a molecule has a + region and a - region |
| polyatomic ion | an ion composed of more than one element |
| pressure | force per unit area |
| proton acceptor | a substance during a reaction that gains a H+ |
| proton donor | a substance during a reaction that loses a H+ |
| quantum theory | the theory of the energy contained in an atom and specific energy levels |
| rate of reaction | the change in concentration in a period of time (M/s) |
| reactant in excess | the substance that is not all consumed during a chemical reaction |
| reactants | the substance brought together to create a chemical |
| reaction forward direction | the reaction consumes reactants and forms products |
| reaction mechanism | the series of steps that a reaction undergoes to completion |
| reaction quotient | the mass action expression for a reversible reaction |
| reaction reverse direction | the reaction consumes products and forms reactants |
| reduction | an element gains electrons |
| reversible reaction | a reaction that occurs in both directions |
| salt | an ionic solid |
| saturated solution | a solution that has the maximum amount of solute dissolved |
| semimetals | elements that have characteristics of both metals and non-metals |
| SI base units | fundimental international system of units used to create compound units |
| single replacement reaction | a reaction where one ion changes place with another |
| solubility | a measure of the ability of a substance to dissolve |
| specific heat | the heat energy needed to raise one gram one degree Celsius |
| spontaneous | a reaction that needs no outside influences to run to completion |
| 101.3kPa | standard atmospheric pressure |
| STP | the reference temperature and pressure 273 degrees K and 101.3 P |
| subatomic particles | the particles that make up the atom |
| sublevels | the energy levels s,p,d,f that make up the primary energy levels |
| synthesis reaction | a reaction where two substances combine to produce a new substance |
| titration | the process of neutralizing an acid with a base or a base with an acid |
| transition element | a metal that fills the d energy sublevel |
| unsaturated | a solution that accept more solute |
| valance electrons | electrons in the outer most energy level responsible for chemical reactions |
| valance shell | the outer most energy level where electrons are located |
| precipitate | the solid particles that drop out of solution during a reaction |
| proton | the subatomic particle responsible for the identity of an element |
| products | the substances created during a chemical reaction |
