Page 333 - Theory and Problems of BEGINNING CHEMISTRY

322 GLOSSARY

2−
peroxide ion O 2 ion.
+
pH −log[H 3 O ].
phase change change of state, as for example change of solid to liquid or solid to gas.
photon a particle of light.
physical change a process in which no change in composition occurs.

pipet a piece of glassware calibrated to deliver an exact volume of liquid.
polyatomic composed of more than one atom.
positron a subatomic particle that may be ejected from a nucleus, with all the properties of an electron except
for the sign of its charge, which is positive.
potential the driving force for electric current.
potential energy energy of position, as for example in a rock on top of a mountain.
precedence the required order of operations in algebra when more than one operation is to be done.

precipitate (1) verb: form a solid from solute in solution. (Form solid or liquid water from the water vapor in
air.) (2) noun: the solid so formed.
pressure force per unit area.

primary amine an amine RNH 2 with one and only one R group.
product element or compound produced in a chemical reaction.
property a characteristic of a substance by which the substance can be identified.
propylene propene; CH 3 CH CH 2 .
+
proton (1) a positive particle in the nucleus of the atom. (2) the H ion (Brønsted-Lowry theory).

2
quadratic formula a formula for solving for x in an equation of the general form ax + bx + c = 0.
√
2
−b ± b − 4ac
x =
2a
quantum (plural, quanta) a particle of energy.
quantum number one of four values that control the properties of the electron in the atom.

R ideal gas law constant: 0.0821 L·atm/(mol·K) or 8.31 J/(mol·K).
R Rydberg constant (see a general chemistry text).
R symbol for a radical in organic chemistry.

radical the hydrocarbon-like portion of an organic compound with one hydrogen atom of the hydrocarbon
replaced by another group.
radioactive decay the disintegration of a sample of a naturally radioactive isotope.

radioactive series a series of isotopes produced one from the other in a sequence of spontaneous radioactive
disintegrations.
rate law an equation that relates the rate of a chemical reaction to the concentrations of its reactants:
x
Rate = k[A] [B] y
rate of reaction the number of moles per liter of product that is produced by a chemical reaction per unit time.