Page 324 - Theory and Problems of BEGINNING CHEMISTRY

GLOSSARY 313

amu atomic mass unit.
-ane name ending for the alkane series of hydrocarbons.

anhydrous without water. The waterless salt capable of forming a hydrate, such as CuSO 4 (which reacts with
water to form CuSO 4 ·5H 2 O).
anion a negative ion.

anode electrode at which oxidation takes place in either a galvanic cell or an electrolysis cell.
aqueous solution a solution in water.
aromatic hydrocarbon a hydrocarbon containing at least one benzene ring, perhaps with hydrogen atoms
replaced by other groups.
Arrhenius theory theory of acids and bases in which acids are defined as hydrogen-containing compounds
−
that react with bases. Bases are defined as OH containing compounds.
aryl radical a hydrocarbon radical derived from the aromatic series.
atmosphere, standard a unit of pressure equal to 760 torr.
atmospheric pressure the pressure of the atmosphere; barometric pressure.
atom the smallest particle of an element that retains the composition of the element.

atomic energy energy from the nuclei of atoms; nuclear energy.
atomic mass the relative mass, compared to that of 12 C, of an average atom of an element.
12
atomic mass unit one-twelfth the mass of a C atom.
atomic number the number of protons in the nucleus of the atom.

atomic theory Dalton’s postulates, based on experimental evidence, which proposed that all matter is composed
of atoms.
autoionization reaction of a substance with itself to produce ions.

auto-oxidation reaction of a substance with itself to produce a product with a lower oxidation number and
another with a higher oxidation number; disproportionation.
Avogadro’s number a mole; 6.02 × 10 23 units; the number of atomic mass units per gram.

balancing an equation adding coefficients to make the numbers of atoms of each element the same on both
sides of an equation.
balancing a nuclear equation ensuring that the total of the charges and the total of the mass numbers are the
same on both sides of a nuclear equation.
barometer a device for measuring gas pressure.
barometric pressure the pressure of the atmosphere.
−
−
base (1) a compound containing OH ions or which reacts with water to form OH ions. (2) a proton acceptor
(Brønsted-Lowry theory).
base of an exponential number the number (or unit) that is multiplied by itself. For example, the base in
3
3
1.5 × 10 is 10, and in 5 cm it is cm.
battery a combination of two or more galvanic cells.
benzene a cyclic compound with molecular formula C 6 H 6 ; the base of the aromatic hydrocarbon series.
beta particle a high-energy electron ejected from a nucleus in a nuclear reaction.