Page 325 - Theory and Problems of BEGINNING CHEMISTRY

314 GLOSSARY

binary composed of two elements.

binding energy the energy equivalent of the difference between the mass of a nucleus and the sum of the
masses of the (uncombined) protons and neutrons that make it up.
Bohr theory the first theory of atomic structure which involved definite internal energy levels for electrons.

Boltzmann constant, k a constant equal to the gas law constant divided by Avogadro’s number: k = 1.38 ×
10 −23 J/molecule·K.
bonding the chemical attraction of atoms for each other within chemical compounds.
Boyle’s law the volume of a given sample of gas at constant temperature is inversely proportional to the pressure
of the gas: V = k/P.
Brønsted-Lowry theory a theory of acids and bases that defines acids as proton donors and bases as proton
acceptors.
buffer solution a solution of a weak acid and its conjugate base or a weak base and its conjugate acid. The
solution resists change in pH even on addition of small quantities of strong acid or base.

buret a calibrated tube used to deliver exact volumes of liquid.
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c (1) symbol for the velocity of light in a vacuum: 3.00 × 10 m/s. (2) symbol for specific heat.
carbonyl group the C O group in an organic compound.

catalyst a substance that alters the rate of a chemical reaction without undergoing permanent change in its own
composition.

cathode electrode at which reduction takes place in either a galvanic cell or an electrolysis cell.
cation a positive ion.
Celsius temperature scale a temperature scale with 0 defined as the freezing point of pure water and 100 ◦
◦
defined as the normal boiling point of pure water.
centi- prefix meaning 0.01.
chain reaction a self-sustaining series of reactions in which the products of one reaction, such as neutrons,
initiate more of the same reaction. One such particle can therefore start a whole series of reactions.
change-sign key the key on a calculator that changes the sign of the number on the display. +/−
Charles’ law for a given sample of gas at constant pressure, the volume is directly proportional to the absolute
temperature: V = kT.
circuit a complete path necessary for an electric current.
classification of matter the grouping of matter into elements, compounds, and mixtures.
coefficient (1) the number placed before the formula of a reactant or product to balance an equation. (2) the
decimal value in a number in standard exponential notation.
coinage metal an element of periodic group IB: Cu, Ag, or Au.
collision theory a theory that explains the effects of the various factors on the rates of chemical reactions in
terms of the particles (molecules, ions, atoms) involved.
combination reaction a reaction in which two elements, an element and a compound, or two compounds
combine to form a single compound.
combined gas law for a given sample of gas, the volume is inversely proportional to the pressure and directly
proportional to the absolute temperature: P 1 V 1 /T 1 = P 2 V 2 /T 2