Chapter 1 Key Terms: Introduction to Chemistry
Chapter 1 Key Terms: Introduction to Chemistry

analytical chemistry- the study of the composition of substances

biochemistry- the study of the composition and behavior of substances in living organisms

chemistry- the study of the structure, properties, and composition of substances, and the changes that substances undergo

experiments- a carefully controlled, repeatable procedure for gathering data to test a hypothesis

*hypothesis- a proposed explanation for observations

inorganic chemistry- primarily the study of substances that do not contain carbon

observation- information obtained through the senses; observation in science often involves a measurement

organic chemistry- the study of compounds that contain the element carbon

physical chemistry- the study of the theoretical basis of chemical behavior, relying on mathematics and physics

*scientific law- a concise statement that summarizes the results of many observations and experiments

*scientific method- a method of inquiry involving observation, experiments, hypotheses, and broad explanations called theories

*theory- a thoroughly tested model that explains why experiments give certain results


Chapter 2 Key Terms: Matter, Change and Energy
*Chemical properties - the ability of a substance to undergo a chemical reaction and to form new substances.

*Chemical reaction - when one or more substances change into a new substance.

Chemical symbol - a one-or-two-letter symbol for each element.

*Compound - substances that can be separated into simpler substances only by chemical means.

Distillation - when a liquid is boiled to produce a vapor that is then condensed again to a liquid.

*Element - the simplest forms of matter that can exist under normal laboratory conditions.

*Gas - a form of matter that takes both the shape and volume of its container.

Heterogeneous mixture - one that is not uniform in composition; has two or more phases.

Homogeneous mixture - one that has a completely uniform composition; has one phase.

Law of conservation of mass - states that in any physical change or chemical reaction, mass is neither created or destroyed; it is conserved.

*Liquid - a form of matter that flows, has a fixed volume, and takes the shape of its container.

*Mass - is the amount of matter the object contains.

*Matter - defined as anything that has mass and takes up space.

*Mixture - a physical blend of two or more substances.

Phase - any part of a system with uniform composition and properties.

*Physical change - a change, which alters a given material without changing its composition.

*Physical property - a quality or condition of a substance that can be observed or measured without changing the substance's composition.

Product - the substance formed in a chemical reaction.

*Reactant - the starting substances in a chemical reaction.

*Solid - matter that has a definite shape and volume.

*Solution - another name for a homogeneous mixture.

Substance - matter that has a uniform and definite composition.

Vapor - describes the gaseous state of a substance that is generally a liquid or solid at room temperature.


Chapter 3 Key Terms: Scientific Measurement
Absolute Zero- the zero point on the Kelvin temperature scale and is equivalent to -273.15 degrees Celsius; all molecular motion theoretically stops at this temperature.

Accepted Value- a quantity used by general agreement of the scientific community.

Accuracy- the closeness of a measure to the true value of what is being measured.

Celsius Scale- the temperature scale on which the freezing point of water is 0 degrees Celsius and the boiling point is 100 degrees Celsius.

Density- the ratio of the mass of an object to its volume.

Error- the difference between the accepted value and the experimental value.

Experimental Value- a quantitative value measured during an experiment.

Gram(g)- a metric mass unit equal to the mass of 1 cubic centimeter (cm^3) of water at 4 degrees Celsius.

Hydrometer- a devise used to measure the specific gravity of a liquid.

International System of Units(SI)- the revised version of the metric system, adopted by international agreement in 1960.

Kelvin Scale- the temperature scale in which the freezing point of water is 273 degrees Kelvin and the boiling point is 373 degrees Kelvin; 0 degrees Kelvin is absolute zero.

Kilogram- the mass of 1 liter of water at 4 degrees Celsius; it is the base unit of mass in SI.

Liter(L)- the volume of a cube measuring 10 centimeters on each edge (1000 cubic centimeters) ; it is the common unprefixed unit of volume in the metric system.

Meter(m)- is the base unit of length in SI.

Percent Error- the percent that a measured value differs from the accepted value.

Precision- describes the closeness, or reproducibility, of a set of measurements taken under the same conditions.

*Qualitative Measurement- a measurement that gives descriptive, nonnumeric results.

*Quantitative Measurement- a measurement that gives definite, usually numeric results.

Scientific Notation- expression of numbers in the form n times 10 to the nth power (n*10^n) where n is equal to or greater than 1 and less than 10 and n is an integer.

*Significant Figures- all the digits that can be known precisely in a measurement, plus a last estimated digit.

Specific Gravity- the ratio of the density of a substance to that of a standard substance (usually water)

Temperature- a measure of the average kinetic energy of particles in matter; temperature determines the direction of heat transfer.

Volume- the space occupied by a sample of matter.

Weight- force that measures the pull of gravity on a given mass.

Chapter 4 Key Terms: Problem Solving in Chemistry
conversion factor - a ratio of equivalent measurements used to convert a quantity from one unit to another

dimensional analysis - a technique of problem-solving that uses the units that are part of a measurement to help solve the problem

Chapter 5 Key Terms: Atomic Structure and the Periodic Table
Alkali metal-any metal in Group 1A of the periodic table

Alkaline earth metal- any metal in Group 2A on the periodic table

*Atom- the smallest particle of an element that retains the properties of that element

Atomic mass- the weighted average of the masses of the isotopes of an element

Atomic mass unit (amu)- a unit of mass equal to one-twelfth the mass of a carbon-12 atom

*Atomic number- the number of protons in the nucleus of an atom of an element

Cathode Ray- a stream of electrons produced at the negative electrode (cathode) of a tube containing a gas at low pressure

Cathode ray tube- a glass tube in which a cathode ray is created

Dalton’s atomic theory- the first theory to relate chemical changes to events at the atomic level

*Electron- a negatively charged subatomic particle found in orbitals around the nucleus

Group- a vertical column of elements in the periodic table; the constituent elements of a group have similar chemical and physical properties

Halogen- any member of the nonmetallic elements in Group 7A of the periodic table

Inner transition metal- an element in the lanthanide and actinide series; characterized by addition of electrons to f orbitals

*Isotope- atoms of the same element that have the same atomic number but different atomic masses due to a different number of neutrons

Mass number- the total number of protons and neutrons in the nucleus of an atom

Metal- one of a class of elements that includes a large majority of the known elements; metals are characteristically lustrous, malleable, ductile, and good conductors of heat and electricity

Metalloid- one of a class of elements having properties intermediate to metals and nonmetals

*Neutron- a subatomic particle with no charge and a mass of 1 amu; found in the nucleus of the atom

Noble gas- any member of a group of gaseous elements in Group 0 of the periodic table; the s and p sublevels of their outermost energy level are filled

Nonmetal- one of a class of elements that are not lustrous and are generally poor conductors of heat and electricity; nonmetals are grouped on the right side of the periodic table

*Nucleus- the dense central portion of an atom, compose of protons and neutrons

Period- a horizontal row of elements in the periodic table

Periodic law- when the elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties

*Periodic table- an arrangement of elements into rows and columns according to similarities in their properties

*Proton- a positively charged subatomic particle found in the nucleus of an atom

Representative elements- Group A element on the periodic table; together, these elements, which have only partially filled outermost s and p sublevels, illustrate the entire range of chemical properties

Transitions metal- Group B element characterized by addition of electrons to d sub-orbitals

Chapter 13 Key Terms: Electrons in Atoms
amplitude - the height of wave from the origin to the crest

atomic emission spectrum - the pattern of frequencies obtained by passing light emitted by atoms of an element in the gaseous state through a prism; the emission spectrum of each element is unique to that element

atomic orbital - a region in space around the nucleus of an atom where there is a high probability of finding an electron

Aufbau principle - electrons enter orbitals of lowest energy first

de Broglie’s equation - an equation that describes the wavelength of a moving particle; it predicts that all matter exhibits wavelike motions

*electromagnetic radiation - a series of energy waves that travel in a vacuum at 3.0 x 1010cm/s: includes radiowaves, microwaves, visible light, infrared and ultraviolet light, x-rays, and gamma rays

electron configuration - the arrangement of electrons around the nucleus of an atom in its ground state

energy level - a region around the nucleus of an atom where an atom where an electron is likely to be moving

frequency - (v) the number of wave cycles that pass a given point per unit of time; there is an inverse relationship between the frequency and wavelength of a wave

ground state - the lowest energy level occupied by an electron when an atom is in its most stable energy state

Heisenburg uncertainty principle - it is impossible to know both the velocity and the position of a particle at the same time

hertz - (Hz) the SI unit of frequency, equal to one cycle per second

Hund’s rule - when electrons occupy orbitals of equal energy, one electron enters each orbital until all orbitals contain one electron with their spins parallel

Pauli exclusion principle - no more than two electrons ca occupy an atomic orbital; these electrons must have opposite spins

photoelectric effect - electrons are ejected by certain metals when they absorb light with a frequency above a threshold frequency

photon - a quantum of light; a discrete bundle of electromagnetic energy that behaves as a particle

Planck’s constant - (h) a number used to calculate the radiant energy absorbed or emitted by a body on the frequency of radiation

quantum - the amount of energy needed to move an electron from its present energy level to the next higher one

quantum mechanical model - the modern description, primarily mathematical, of the behavior of electrons in atoms

spectrum - range of wavelengths of electromagnetic radiation; wavelengths of visible light are separated when a beam of white light passes through a prism

*wavelength - (l) the distance between two adjacent crests of a wave

orbital notation - method of recording the position and spin of electrons around an element with arrows representing the electrons

Schrodinger - physicist who's mathematical model (the quantum mechanical model) describes the position and energy of electrons around a nucleus

Chapter 14 Key Terms: Chemical Periodicity
atomic radius - one-half the distance between the nuclei in a molecule consisting of identical atoms

electronegativity- the tendency for an atom to attract electrons to itself when it is chemically combined with another element

inner transition metal - an element in the lanthanide and actinide series; characterized by addition of electrons to f orbitals

ionization energy -the energy required to remove an electron from a gaseous atom

noble gas - any member of a group of gaseous elements in Group 0 or 18 or VIII A

representative element - Group A element on the periodic table; together, these elements, which have only partially filled outermost s an p sub levels, illustrate the entire range of chemical properties

transition metal - Group B element characterized by addition of electrons to d suborbitals

Chapter 24 Key Terms: Chemistry of Metals and Nonmetals
inner transition element - an element in the lanthanide and actinide series; characterized by addition of electrons to f orbitals

lime - calcium oxide (CaO); it is sometimes called quick lime

metallurgy -the various procedures used to separate metals from their ores

Monel metal - a strong, corrosion-resistant alloy of nickel and nickel

ore - a mineral used for commercial production of a metal

slaked lime - (Ca(OH)2) calcium hydroxide

Chapter 28 Key Terms: Nuclear Chemistry
Alpha particle:  A positively charged particle emitted from certain radioactive nuclei; it consists of two protons and two neutrons and is identical to the nucleus of a helium atom

Alpha radiation:  Alpha particles emitted from a radioactive source

Band of stability:  The location of stable nuclei on a neutrons-vs-proton plot

Beta particle:  A fast-moving electron emitted from certain radioactive nuclei; it is formed when a neutron decomposes into a proton and an electron

Beta radiation:  Fast-moving electrons (beta particles) emitted from a radioactive source

Film badge:  A small radiation detector worn by persons who work near radiation sources; it consists of several layers of photographic film covered with black lightproof paper encased in a plastic or metal holder

Fission:  The splitting of a nucleus into smaller fragments, accompanied by the release of neutrons and a large amount of energy

Fusion:  A reaction in which two light nuclei combine to produce a nucleus of heavier mass, accompanied by the release of a large amount of energy

Gamma radiation:  High energy electromagnetic radiation emitted by certain radioactive nuclei; gamma rays have no mass or electrical charge

Geiger counter:  a gas-filled metal tube used to detect the presence of beta radiation

Half-life:  The time required for one-half of the nuclei of a radioisotope sample to decay

Ionizing radiation:  Radiation with enough energy to knock electrons off some atoms of the bombarded substance to produce ions

Neutron absorption:  A process that decreases the number of slow moving neutrons

Neutron moderation:  A process that reduces the speed of neutrons so they can be captured by the reactor fuel in order to continue the chain reaction

Positron:  A particle with the mass of an electron but a positive charge

Radiation:  The penetrating rays and particle emitted by a radioactive source

Radioactive decay:  The spontaneous emission of radiation by an unstable nucleus; the rate of decay is unaffected by temperature, pressure, or catalysts

Radioactivity:  The process by which unstable atomic nuclei achieve stability

Radioisotopes:  The nuclei of unstable isotopes

Scintillation counter:  A device that uses a specially coated phosphor surface to detect radiation

Transmutation:  The conversion of an atom of one element to an atom of another element

Transuranium element:  An element in the periodic table with an atomic number that is grater than 92

Chapter 6 Key Terms: Chemical Names and Formulas
binary compound - a compound composed of two elements; NaCl and Al2O3

ionic compound - a compound composed of positive and negative ions

*acid - a compound that produces hydrogen ions in solution, is a hydrogen-ion donor, or an electron-pair acceptor

*base - a compound that produces hydroxide ions in solution, is a hydrogen-ion acceptor, or an electron-pair donor

group - a vertical column of elements in the periodic table; the constituent elements of a group have similar chemical and physical properties

metal - one of a class of elements that includes a large majority of the known elements; metals are characteristically lustrous, malleable ductile and good conductors of heat and electricity

metalloid -one of a class of elements having properties intermediate to metals and nonmetals

nonmetal - one of a class of elements that are not lustrous and are generally poor conductors of heat and electricity; nonmetals are grouped on the right side of the periodic table

*periodic table - an arrangement of elements into rows and columns according to similarities in their properties

representative element - Group A element on the periodic table; together, these elements, which have only partially filled outermost s and p sublevels, illustrate the entire range of chemical properties

semimetal - metalloid

transition metal - Group B element characterized by addition of electrons to d suborbitals

*Molecule- the smallest electrically neutral unit of a substance that still has properties of a substance.

Molecular Compounds- compounds composed of molecules.

*Ions- atoms or groups of atoms that have a positive or negative charge.

Cation- any atom or group of atoms that have a positive charge.

Anion- atoms or group of atoms that have a negative charge.

Ionic Charge- Compounds composed of cations and anions.

Chemical Formula- shows the kinds and numbers of atoms in the smallest representative unit of the substance.

Molecular Formula- shows the kinds and numbers of atoms present in a molecule of a compound.

Formula Unit- the lowest whole- number ratio of ions in the compound.

Law of Definite Proportions- states that in samples of any chemical compound, the masses of the elements are always in the same proportions.

Law of Multiple Proportions- whenever two elements form more than one compound, the different masses of one element that combine with the same mass of the other element are in the ratio of small whole number.

Monatomic Ions- ions that consist of only one atom.

Polyatomic Ions- tightly bound groups of atoms that behave as a unit and carry a charge.

Binary Compounds- compounds composed of two elements.

Ternary Compounds- a compound that contains atoms of three different elements.


Chapter 7 Key Terms: Chemical Quantities
Avagadro's Number - The number of representative particles contained in one mole of a substance; equal to 6.02x10^23 particles.

emperical formula - A formula with the lowest whole-number ratio of elements in a compound; the emperical formula of hydrogen peroxide (H2O2) is HO.

gram atomic mass - The mass, in grams, of one mole of atoms in a monatomic element; it is numerically equal to the atomic mass in amu.

gram formula mass - The mass of one mole of an ionic compound.

gram molecular mass - The mass, in grams, on one mole of a molecular substance.

molar mass - A general expression used to refer to the mass of a mole of any substance unless a more specific term is needed to avoid confusion.

molar volume - The volume occupied by 1 mole of a gas at standard temperature and pressure.

mole - The amount of a substance that contains 6.02x10^23 representative particles of that substance.

percent composition - The percent by mass of each element in a compound.

representative particle - The smallest unit into which a substance can be broken down without a change in composition; the term refers to whether a substance commonly exists as atoms, ions, or molecules.

standard temperature - The condition under which the volume of a gas is usually measured; 0 degrees Celcius

standard pressure - The condition under which the volume of a gas is usually measured; 1 atmosphere (atm)


Chapter 8 Key Terms: Chemical Reactions
Activity Series of Metals- a table listing metals in ores of decreasing activity.

Balanced Equation- a chemical equation in which mass is conserved; each side of the equation has the same number of atoms of each element.

Catalyst- a substance that increases the rate of reaction by lowering the activation-energy barrier; the catalyst is not used up.

Chemical Equation- an expression representing a chemical reaction; the formulas of the reactants (on the left) are connected by an arrow with the formulas for the products (on the right).

Coefficient- a small whole number that appears in front of a formula in a balanced chemical equation.

Combination Reaction- a chemical change in which two or more substances react of form a single new substance; also called a synthesis reaction.

Combustion Reaction- a chemical reaction change in which oxygen reacts with another substance, often producing energy in the form of heat and light.

Complete Ionic Equation- an equation for a reaction in solution showing all strong electrolytes as ions.

Decomposition Reaction- a chemical change in which a single compound is broken down into two or more simpler products.

Double-Replacement Reaction- a chemical change that involves an exchange of positive ions between two compounds.

Net Ionic Equation- an equation for a reaction in solution showing only those particles that are directly involved in the chemical change.

Single-Replacement Reaction- a chemical change in which one element replaces a second element in a compound; also called a displacement reaction.

Skeleton Equation- a chemical equation that does not indicate the relative amounts of reactants and products.

Spectator Ion- an ion that is not directly involved in a chemical reaction; an ion that does not change oxidation number composition during a reaction.

Chapter 9 Key Terms: Stoichiometry
Stoichiometry- the calculation of quantities in chemical reactions.

Limiting reagent- limits or determines the amount of product that can be formed in a reaction.

Excess reagent- a reactant that is not completely used up in a reaction.

Theoretical yield- the maximum amount of product that could be formed from given amounts of reactants.

Actual yield- the amount of product that actually forms when the reaction is carried out in the laboratory.

Percent yield- the ratio of the actual yield to the theoretical yield expressed as a percent.



Chapter 10 Key Terms: States of Matter
allotrope- 1 of 2 or more different molecular forms of an element in some physical state; oxygen (02) and ozone are allotropes of the element.

amorphous solid- term used to describe solid that lacks ordered internal structure; denotes random arrangement of atoms.

*atmospheric pressure- pressure exerted by air molecules in atmosphere surrounding Earth, resulting from collisions of air molecules with objects.

*barometer- device used to measure atmospheric pressure.

boiling point- temp. at which vapor pressure of a liquid is just equal to external pressure on the liquid.

*crystal- substance at which atoms, ions, or molecules are arranged in orderly, repeating 3-D pattern called crystal lattice.

*evaporation- vaporizing that occurs at the surface of a liquid (not boiling).

gas pressure- force exerted by gas per unit surface area of an object; due to collisions of gas particles with the object.

glass- optically transparent fusion product of inorganic materials that have cooled to rigid state without crystallizing.

*kinetic energy- energy an object has because of its motion.

kinetic theory- explaining states of matter, based on concept that particles in all forms of matter are in constant motion.

melting point- temperature at which substance changes from solid to liquid (water is 0degrees C)

normal melting point- melting/boiling point of a liquid at a pressure of 1 atmosphere.

Pascal- SI unit of pressure

phase diagram- shows conditions of substances existing as a solid, liquid, or vapor

standard atmosphere- unit of pressure; it’s the pressure required to support 760mm of HG in a mercury barometer @ 25 degrees Celsius; this is average atmospheric pressure at sea level.

sublimation- conversion of solid to gas or vapor without passing through liquid state.

triple point- point on phase diagram that represents only set of conditions at which all three exist in equilibrium with one another

unit cell- smallest group of particles within a crystal that retains the geometric shape of the crystal

vacuum- space where no particles of matter exist.

vaporization- conversion of a liquid to gas or vapor.

vapor pressure- pressure produced when vapor particles above a liquid in a sealed container collide with the container walls; dynamic equilibrium exists between the vapor and the liquid.

Chapter 12 Key Terms: The Behavior of Gases
Avagadro's hypothesis - equal volumes of gases at the same temperature and pressure contain equal number of particles

Boyle's law - for a fixed mass of gas at constant temperature, the volume of the gas varies inversely with pressure

Charles' law - the volume of a fixed mass of gas is directly proportional to its Kelvin temperature if the pressure is kept constant

combined gas law - a relationship describing the behavior of gases that combines Boyles' Law, Charles' Law and Gay-Lussac's Law

compressibility - a measure of how much the volume of matter decreases under pressure

Dalton's law of partial pressure - at constant volume and temperature, the total pressure of a mixture of gases is the sum of the partial pressures of all the gases present

diffusion - the tendency of molecules and ions to move toward areas of lower concentration until the concentration until the concentration is uniform throughout the system

effusion - a process that occurs when a gas escapes through a tiny hole in its container

Gay-Lussac's law - the pressure and Kelvin temperature of a gas are directly proportional at a constant volume

Graham's law of effusion - the rate of effusion of a gas is inversely proportional to the square root of its molar mass; this relationship is also true for the diffusion of gases

ideal gas law - the relationship PV = nRT, which describes the behavior of an ideal gas

partial pressure - the pressure exerted by each gas in a gaseous mixture

Chapter 9 (15) Key Terms: Ionic Bonding and Ionic Compounds
coordination number - the number of ions of opposite charge that surround each ion in a crystal

electron dot structure - a notation that depicts valence electrons as dots around the atomic symbol of the element; the symbol represents the inner electrons and atomic nucleus; also called Lewis dot structures

halide ion - a negative ion formed when a halogen atom gains an electron

ionic bond - the electrostatic attraction that binds oppositely charged ions together

metallic bond - the force of attraction that holds metals together; it consists of the attraction of free-floating valence electrons for positively charged metal ions

octet rule - atoms react by gaining or losing electrons so as to acquire the stable electron structure of a noble gas, usually eight valence electrons

valence electron - an electron in the highest occupied energy level of an atom

Chapter 8 (16) Key Terms: Covalent Bonding
ANTIBONDING ORBITAL:    molecular orbital with an energy that is higher than that of the atomic orbitals from which it is formed.

BOND DISASSOCIATION ENERGY:  amount of energy required to break a covalent bond between atoms; this value is usually expressed in KJ per mol of substance.

BONDING ORBITAL: a molecular orbital whose energy is lower than that of the atomic orbitals from which it is formed.

COORDINATE COVALENT BOND: covalent bond formed when one atom contributes both bonding electrons.

DIAMAGNETIC:  substance that is weakly repelled by a magnetic field.

DIPOLE:  molecule that has two electrically charged regions or poles.

DIPOLE INTERACTION:  a weak inter molecular force resulting from the attraction of oppositely charged regions of polar molecules.

DISPERSION FORCE:  the weakest kind of intermolecular attraction; this attraction is thought to be caused by the motion of electrons.

DOUBLE COVALENT BOND:  covalent bond in which two pairs of electrons are shared by two atoms.

HYBRIDIZATION:  process in which several atomic orbitals mix to form the same number of equivalent hybrid orbitals.

HYDROGEN BOND:  relatively strong intermolecular force in which a hydrogen atom that is covalently bonded to a very electronegative atom is also weaky bonded to an unshared electron pair of another electronegative atom in the same molecular or one near by.

MOLECULAR ORBITAL:  orbital resulting from the overlapping of atomic orbitals when two atoms combine.

NETWORK SOLID:  substance in which all of the atoms are covalently bonded to each other.

NONPOLAR COVALENT BOND:  bond formed when the atoms in a molecule are alike and the bonding electrons are shared equally.

PARAMAGNETIC:  term used to describe a substance that shows a relatively strong attraction to an external magnetic field:  these substances have molecules containing one or more unpaired electrons.

PI BOND:  bond in which the bonding electrons are most likely to be found in the sausage-shaped regions above and below the nuclei of the bonded atoms.

POLAR BOND:  bond formed when two different atoms are joined by a covalent bond and the bonding electrons are shared unequally.

POLAR COVALENT BOND:  same as polar bond.

POLAR MOLECULE:  molecule, like water, in which one or more atoms is slightly negative and one or more is slightly positive, unless molecular geometry cause the polarities to cancel each other out.

RESONANCE STRUCTURE:  one of two or more equally valid electron dot structures for a molecule or polyatomic ion; the actual bonding is a hybrid, or mixture, of the resonance structures.

SIGMA BOND:  bond formed when two atomic orbitals combine to form a molecular orbital that is symmetrical along the axis connecting the two atomic nuclei.

SINGLE COVALENT BOND:  bond formed when a pair of electrons is shared between two atoms.

STRUCTURAL FORMULA:  chemical formula that shows the arrangement of atoms in a molecule or a polyatomic ion; each dash between two atoms indicates a pair of shared electrons.

TETRAHEDRAL ANGLE:  bond angle of 109.5 created when a central action forms four bonds directed toward the corners of a regular tetrahedron.

TRIPLE COVALENT BOND:  covalent bond in which three pairs of electrons are shared by two atoms.

UNSHARED PAIR:  pair of valence electrons that are not involved in bonding.

VANDER WAALS FORCE:  term used to describe the weakest intermolecular attractions; these include dispersion forces and dipole interation.

VSEPR THEORY:  valance - shell electron pair repulsion theory; because electron pairs repel, molecules adjust their shapes so that valence - electron pairs are as far apart as possible.

Chapter 17 Key Terms: Water and Aqueous Systems
Aqueous solutions – water substances containing dissolved substances.

Brownian motion – the chaotic movement of colloidal particles.

Colloid – heterogeneous mixtures containing particles that are intermediate in size between those of suspensions and true solutions.

Deliquescent – are compounds that remove sufficient water from the air to dissolve completely and form solutions.

Effloresce – loosing the water of hydration. The process occurs when the hydrate has a vapor pressure higher than that of water vapor in the air.

Electrolyte – a compound that conducts an electric current in aqueous solution or in the molten state.

Emulsion – the colloidal dispersion of one liquid in another.

Hygroscopic – a term describing salts and other compounds that remove moisture from the air.

Non-electrolyte – a compound that does not conduct an electric current in aqueous solution or in the molten state.

Solute – dissolved particles in a solution

Solvation – a process that occurs when an ionic solute dissolves.

Solvent – the dissolving medium in a solution.

Strong Electrolyte – a solution in which a large portion of the solute exists as ions.

Surface tension – an inward force that tends to minimize the surface area of a liquid.

Surfactant – a surface-active agent; any substance with molecules that interfere with the hydrogen bonding between water molecules, reducing surface tension.

Suspension – a mixture from which some of the particles settle out slowly upon standing.

Tyndall Effect – scattering of light by particles in a colloid or suspension, which causes a beam of light to become visible.

Water of Hydration – water molecules that are an integral part of a crystal structure.

Weak Electrolyte – a solution in which only a fraction of the solute exists as ions.

Chapter 18 Key Terms: Solutions
Boiling-point elevation-the difference in temperature between the boiling point of a solution and of the pure solvent

Colligative property-a property of a solution that depends only on the number of the solute particles; boiling point elevation, freezing-point elevation, freezing-point depression, and vapor-pressure lowering are colligative properties

Concentrated solution-a solution containing a large amount of solute

Concentration-a measurement of the amount of solute that is dissolved in a given quantity of solvent; usually expressed as mol/L

Dilute solution-a solution that contains a small amount of solute

Freezing-point depression-the difference in temperature between the freezing point of a solution and of the pure solvent

Henry's law-at a given temperature the solubility of a gas in a liquid is directly proportional to the pressure of the gas above the liquid

Immiscible-describes liquids that are insoluble in one another; oil and water are immiscible

Miscible-describes liquids that dissolve in one another

Molal boiling-point elevation constant (Kb)-the change in boiling point for a 1-molal solution of a nonvolatile molecular solute

Molal freezing-point depression constant (Kf)-the change in freezing point for a 1-molal solution of a nonvolatile molecular solute

Molality (m)-the concentration of solute in a solution expressed as the number of moles of solute dissolved in kilogram (1000 g) of solvent

Molarity (M)-the concentration of solute in a solution expressed as the number of moles of solute dissolved in 1 liter of solution

Mole fraction-the ratio of the moles of solute in solution to the total number of moles of both solvent and solution

Saturated solution-a solution containing the maximum amount of solute for a given amount of solvent at a constant temperature and pressure; and equilibrium exists between undeserved solute and ions in solution

Supersaturated solution-a solution that contains more solute than it can theoretically hold at a given temperature; excess solute precipitates if a seed crystal is added

Unsaturated-a solution that contains less solute than a saturated solutions

 

Chapter 20 Key Terms: Acids and Bases
*Acid-a compound that produces hydronium ions when dissolved in water

*Base-a compound that produces hydroxide ions when dissolved in water

Hydroxide Ion-A water molecule that loses a hydrogen ion and becomes a negatively charged hydroxide ion

Hydronium Ion-A water molecule that gains a hydrogen ion positively charged hydronium ion

Self-ionization-The reaction in which two water molecules produce ions

Neutral solution-Any aqueous solution in which [H +] an [OH -] are equal

Ion-product constant for water-The product of the concentrations of the hydrogen ions and hydroxide ions in water

*Acidic solution-One in which [H +] is greater than [OH -]

*Basic solution-One in which [H +] is less than [OH -]

Alkaline solutions-basic solutions are also known as alkaline solutions

*pH-The negative logarithm of the hydrogen-ion concentration

Acid-base indicators- An acid or a base that undergoes dissociation in a known pH range

pH meters-Used to make rapid, accurate pH measurements

Monoprotic acids-Acids that contain one ionizable hydrogen

Diprotic acids-Acids that contain two ionizable hydrogens

Triprotic acids-Acids that contain three ionizable hydrogens

Hydrogen-ion donor-The Bronsted-Lowry theory defines an acid as a hydrogen-ion donor

Hydrogen-ion acceptor-A Bronsted-Lowry base is a hydrogen-ion acceptor

Conjugate acid-The particle formed when a base gains a hydrogen ion

Conjugate base-The particle that remains when an acid has donated a hydrogen ion

Conjugate acid-base pair-Consists of two substances related by the loss or gain of a single hydrogen ion

Amphoteric-A substance that can act as both an acid and a base

Lewis acid-A substance that can accept a pair of electrons to form a covalent bond

Lewis base-A substance that can donate a pair of electrons to form a covalent bond

Strong acids-Completely ionized in aqueous solution

Weak acids-Ionize only slightly in aqueous solution

Acid dissociation constant-The ration of the concentration of the dissociated form of an acid to the concentration of the undissociated form

Base dissociation constant-The ratio of the concentration of the conjugate acid times the concentration of the hydroxide ion to the concentration of the conjugate base


Chapter 11 Key Terms: Thermochemistry - Heat and Chemical Change
calorie (cal)- the quantity of heat that raises the temperature of 1g of pure water to 1° C. calorimeter- a device for measuring heat changes.

calorimeter- device used to measure heat

calorimetry- the measurement of heat changes for physical and chemical processes.

chemical potential energy- energy stored within the structural units of chemical substances.

*endothermic process- a heat-absorbing process.

*energy- the capacity for doing work; it exists in several forms , including chemical, nuclear, electrical, radiant, mechanical, and thermal energies.

enthalpy- for systems at constant pressure, the heat content is the same as a property.
*exothermic process- a heat-dissipating process.

heat- the energy that is transferred from one body to another because of a temperature difference.

heat capacity- the quantity of heat required to change an object’s temperature by exactly 1° C.

heat of combustion- the heat released during a chemical reaction in which one mole of a substance is completely burned.

heat of reaction- the heat released or absorbed during a chemical reaction; equivalent to h, the change in enthalpy.

Hess's law of heat summation- in going from a particular set of reactants to a particular set of products, the enthalpy change is the same whether the reaction takes place in one step or in a series of steps.

joule (j)- the SI unit of energy; 4.184J equal 1 calorie.

law of conservation of energy- energy is neither created nor destroyed in an ordinary chemical of physical process.

molar heat of condensation- the heat, joules or calories, released by 1 mole of a substance as it changes from a vapor to a liquid at the liquid’s boiling point.

molar heat of fusion- the energy, in kilojoules, required to melt 1 mole of a solid.

molar heat of solidification- the heat, in joules or calories, released by 1 mole of a substance as it changes from a liquid to a solid at the solid’s melting point.

molar heat of solution- the heat, in joules or calories, released or absorbed by 1 mole of a substance as it dissolves in water to produce1 liter of a 1 molar solution.

molar heat of vaporization- the energy, in kilojoules, required to vaporize 1 mole of a liquid.

specific heat capacity- the quantity of heat, in joules or calories, required to raise the temperature of 1 g of a substance 1° C.

standard heat of formation- the change in enthalpy for a reaction in which one mole of a compound is formed for its constituent elements.

surroundings- the remainder of the universe that is outside the system.

*system – any part of the universe upon which attention is focused.

thermochemical equation- a chemical equation that includes the amount of heat produced or absorbed during the reaction.

thermochemistry- the study of heat changes in chemical reactions.
universe- the totality of all existing things.


Chapter 19 Key Terms: Reaction Rates and Equilibrium
activated complex - an unstable arrangement of atoms that exists momentarily at the peak of the activation energy barrier; an intermediate or transitional structure formed during the course of a reaction.

activation energy - the minimum energy colliding particles must have in order to react.

catalyst - a substance that increases the rate of reaction by lowering the activation energy barrier; the catalyst is not used up.

chemical equilibrium - a state of balance in which forward and reverse reactions are taking place at the same rate; no net change in the amounts of reactants and products occurs in the chemical system.

collision theory - atoms, ions, and molecules can react to form products when they collide, provided that the particles have enough kinetic energy.

elementary reaction - a reaction in which reactants are converted to products in a single step.

*entropy - a measure of the disorder of a system; systems tend to go from state of order to a state of maximum disorder.

equilibrium constant - the ratio of product concentrations to reactant concentrations at equilibrium with each concentration raised to a power equal to the number of moles of that substance in the balanced chemical equation.

equilibrium position - the relative concentrations of reactants and products of a reaction that has reached equilibrium; indicates whether the reactants or products are favored in the reversible reaction.

first-order reaction - a reaction in which the reaction rate is proportional to the concentration of only one reactant.

free energy - the energy available to do work.

Gibbs free energy change - the maximum amount of energy that can be coupled to another process to do useful work.

inhibitor - a substance that interferes with the action of a catalyst.

intermediate - a product of a reaction that immediately becomes a reactant of another reaction.

law of disorder - it is a natural tendency of systems to move in the direction of maximum chaos or disorder.

Le Chatelier principle - when stress is applied to a system at equilibrium, the system changes to relieve the stress.

nonspontaneous reaction - a reaction that does not favor the formation of products at the specified conditions.

rate - describes the speed of change over an interval of time.

rate law - an expression relating the rate of a reaction to the concentration of the reactants.

reaction mechanism - a series of elementary reactions that take place during the course of a complex reactions.

reversible reaction - a reaction in which the conversion of reactants into products and the conversion of products into reactants occur simultaneously.

specific rate constant - a proportionality constant relating the concentrations of reactants to the rate of the reaction.

spontaneous reaction - a reaction that favors the formation of products at the specified conditions; spontaneity depends on enthalpy and entropy changes.

standard entropy - the entropy of a substance in its state at 25 degrees Celsius and 1 atm.

transition state - a term sometimes used to refer to the activated complex.