Barron's AP Chemistry 7th Edition - Vocabulary

Absolute uncertainty

Absolute uncertainty

The uncertainty of +_1 in the last digit of a measurement. If this uncertainty is different from +_1, it is written as part of the number; e.g 23.45+_0.05 indicates an uncertainty of +_5 in the last digit.

Absolute zero

The lowest possible temperature, 0.0 K or -273.16 degree Celsius

Absorbance, A

A measure of the amount of light absorbed by a chemical

Absorptivity, a

A constant the value of which depends on the sample and the wavelength at which the measurement is made in spectroscopy

Accuracy

The degree of closeness between a measured value and the true value

Acid

Any substance that donates protons, or as Lewis acids are electron - pair acceptors

Acid anhydride

The oxide of a nonmetal that forms an acid when dissolved in water

Acid dissociation constant, Ka

The value of the equilibrium expression for the dissociation of a weak acid

Activated complex

The structure of colliding molecules at the moment of collision, generally thought to be intermediate between the structures of the products and of the reactants.

Activation energy

The increase in potential energy, due to a molecular collision, necessary to convert a reactant into a product.

Activity series

A listing of elemental substances in the order of their ability to be oxidized or reduced. This listing makes it possible to predict whether an element will cause the oxidation or the reduction of an ion of another element

Addition reaction

The reaction in which a double bond opens to form two additional single bonds.

Adhesive force

The attractive force between two dissimilar substances

Alcohol

An organic compound with an -OH group

Aldehyde

An organic compound with a terminal -CHO group

Alkali metals

The extremely reactive elements in the first group (column) of the periodic table. They all have ns1 electrons as valence electrons.

Alkaline earth metals

The very reactive elements in the second group (column) of the periodic table. They all have ns2 electrons as valence electrons.

Alkanes

Organic compounds with the general formula CnH2n+2

Alkenes

Organic compounds with double bonds in their structures

Alkyl group

A functional group that is Alkane in nature

Alkynes

Organic compounds with triple bonds in their structures

Allotrope

One or more distinct forms of an element; classification as an allotrope is based on structure and physical properties, e.g diamond and graphite are two allotropes of carbon

Alpha particle

A helium nucleus

Amines

Compounds, related to ammonia, in which one or more of the hydrogen atoms in ammonia have been replaces by organic functional groups

Amino acid

An organic acid that contains both an amine and an acid functional group on adjacent carbon atoms

Amorphous

A term meaning without structure

Amphiprotic

A term describing a substance that can donate a proton and accept a proton

Amphoteric

A term describing a substance that can act as an acid or as a base

Anhydride

The oxide of a metal or nonmetal that reacts with water to form a acid or a base, respectively

Anion

An ion with a negative charge

Aqueous

A term designating a system that involves water or a chemical mixture or solution having water as the solvent

Arrhenius equation

The equation that relates temperature to rate constant. K=Ae_Ea/RT.

Arrhenius theory

The theory that an acid increases hydrogen ion concentration when dissolved and that a base increase hydroxide ion concentration when dissolved

Aryl group

A functional group that is aromatic in nature

Atom

A fundamental particle of chemistry. At present, 109 atoms are known and are arranged in an orderly manner in the periodic table.

Atomic mass, A

The relative mass of an element as compared to the mass of the isotope C-12, which is defined as exactly 12

Atomic number, Z

The number of an element in the periodic table; also, a number representing the number of protons in the nucleus of an atom.

Atomic orbital

The orbital structure of an element; also, an orbital within an element.

Atomic symbol

A one or two letter abbreviation of an elements name. Some symbols (Pb for lead) are derived from Latin names of the elements.

Autopyrolysis constant of water, Kw

The value of the equilibrium expression for the dissociation of water into H+ and OH_

Avogadro's number

A quantity equal to 6.022 X 10^23

Avogadro's principle

A statement of the direct relationship between the moles of a gas and the volume of that gas.

Axial atom

A term used to describe the position of an atom in a covalent molecule of the AX5 or AX6 basic structure. The axial atom are on the vertical axis of the molecule in positions similar to the Earth's North and South Poles.

Azimuthal quantum number, l

The quantum number that specifies the sublevel in which an electron is located; l may be any number from zero up to n_1

Balanced reaction

A chemical equation that has the smallest whole number coefficients for the reactions and products so that there is the same number of atoms of each element on both sides of the arrow.

Barometer

A closed end manometer used for measuring atomsphere pressure

Base

Any compound that increases the hydroxide concentration of a solution or is a proton acceptor. Lewis bases are electron pair donors.

Base dissociation constant, Kb

The value of the equilibrium expression for the dissociation of a weak base.

Basic structure

One of five basic geometries linear, triangular planar, tetrahedral, trigonal planar, or octahedral that a molecule may take.

Base anhydride

The oxide of a metal that forms a base when dissolved in water.

Battery

A galvanic cell used to produce electricity for consumer items such as flashlights, portable radios, and heart pacemakers.

Beer's law

The statements that the absorbance of a sample is the product of the absorptivity, optical path length, and sample concentration; A=abc.

Beta particle

An electron

Bidentate ligand

A Lewis base that donates two pairs of electrons.

Binary acid

An acid that contains hydrogen and one other element in its formula.

Body-centered cubic (bcc)

A cubic structure in which one atom is at each of the eight corners and one atom is in the center of the unit cell.

Bohr atom

The model of the atom developed by Niels Bohr. This model views electrons as circling the nucleus like a miniature solar system.

Boiling point, normal

The temperature at which the vapor pressure of a liquid is equal to 760 millimeters of mercury (1.00 atmospheres): also, the temperature at which a gas condenses, also called condensation point.

Boiling-point-elevation constant, Kb

The temperature increase of the boiling point per molal noun of solute particles.

Bonding electron pair

A pair of electrons that participate in a covalent bond.

Bond order

The average number of bonds per atom covalently bonded to a central atom.

Boyle's law

The law that expresses the inverse relationship between the volume and the pressure of a gas; PV = constant.

Bragg equation

The equation that relates the atomic dimensions in a crystal to the angles at which monochromatic X-Rays will undergo constructive reinforcement

Bronsted-Lowry theory

The theory that acids are proton donors and bases are proton acceptors.

Buckminsterfullerene

The allotrope of carbon that has the formula C60.

Buffer capacity

The moles of strong acid or stronge base required to change the pH of a liter of buffer by 1 pH unit.

Buffer solution

An aqueous solution containing a conjugate acid and its conjugate base a molar ratio greater than 0.1 and less than 10.0.

Bumping

The violent boiling that occurs when a solution becomes superheated.

Buret

A tube approximately 1 centimeter in diameter that is used for measuring liquid volumes of 10-100 milliliters

Calorimeter

An instrument used to determine heat energy

Catalyst

A substance that speeds up the rate of a chemical reaction by providing an alternative reaction pathway with a lower activation energy

Cation

An ion with a positive charge.

Cell voltage, E

The voltage of a galvanic cell under nonstandard state conditions.

Centrifugation

The process of separating a solid from a liquid by spinning it rapidly to artificially increase the gravitational force.

Change reaction

A nuclear reaction that produces more neutrons than were needed to initiate it, therefore causing more reactions than occurred in the preceding step.

Charles's law

The law that expresses the direct relationship between the temperature and volume of a gas: P/V = constant

Chelate

A Lewis base that usually has more than one pair of electrons to donate.

Cis isomer

An isomer with substituents on the same side of the double bond.

Close system

A system in which mass cannot be lost to or gained from the surroundings.

Coefficient

A number placed in front of a chemical formula to represent the number of molecules of that substance that are included in the equation. This number multiplies the number of atoms in the formula unit.

Cohesive force

The sum of all the attractive forces in a pure substance

Colligative property

Any one of several physical properties of a solution that change depending on the amount of solute particles present in the solution.

Collision theory

The theory of kinetics, which relates reaction rates to the frequency, energy and orientation of molecules in collisions.

Complexation reaction

A reaction between a Lewis acid and a Lewis base.

Complex or Complex ion

A combination of one or more compounds or anions with a metal ion by coordination covalent bonding, also called complex.

Compound

A combination of two or more elements into a distinct substance with definite physical properties.

Concentrated

A qualitative term indicating a large amount of solute in a given amount of solvent.

Concentration

An expression of the amount of solute mixed with a solvent.

Concentration vs time curve

A graph of reactant or product concentration as a function of time

Condensation

The conversion of gas into a liquid.

Condensation reaction

A polymerization reaction between an acid and either an alcohol or an amine.

Conjugate acid

Any substance that has a proton that may be donated to a base.

Conjugate acid-base pair

A pair of substances whose formulas differ by one H+ ion.

Conjugate double bonds

A series of two or more double bonds, each separated by only a single bond in a molecule.

Cooling curve

A graph showing the changes that occur while a substance is cooling.

Coordinate covalent bond

The covalent bond between two atoms that is formed when one substance donates both electrons.

Covalent bond

The bond between two atoms that arises from the sharing of a pair of electrons

Covalent compound

A chemical compound in which the atoms are held together with covalent bonds

Covalent crystal

The crystal that consists of only one molecule. All atoms are joined to others with covalent bonds. Also called network crystal

Critical mass

The minimum mass of a fissile (fissionable)material needed to sustain a nuclear chain reaction.