386 ❯ Glossarycrystalline solids Crystalline solids display a very
regular ordering of the particles (atoms, molecules,
or ions) in a three-dimensional structure called
the crystal lattice.
Dalton’s law Dalton’s law states that in a mixture of
gases (A + B + C.. .) the total pressure is simply
the sum of the partial pressures (the pressures
associated with each individual gas).
decomposition reactions Decomposition reactions
are reactions in which a compound breaks down
into two or more simpler substances.
diamagnetism Diamagnetism is the repulsion of
a molecule from a magnetic field due to the
presence of all electrons in pairs.
dilute Dilute is a qualitative term that refers to
a solution that has a relatively small amount of
solute in comparison to the amount of solvent.
dimensional analysis Dimensional analysis, sometimes
called the factor label method, is a method for gen-
erating a correct setup for a mathematical problem.
dipole–dipole intermolecular force Dipole–dipole
intermolecular forces occur between polar molecules.
double displacement (replacement) or metathesis
reaction A double displacement (replacement) or
metathesis reaction is a chemical reaction where
at least one insoluble product is formed from the
mixing of two solutions.
effective nuclear charge The overall attraction that
an electron experiences is called the effective nuclear
charge. This is less than the actual nuclear charge,
because other electrons interfere with the attraction
of the protons for the electron being considered.
electrochemical cells Electrochemical cells use
indirect electron transfer to produce electricity by
a redox reaction, or they use electricity to produce
a desired redox reaction.
electrochemistry Electrochemistry is the study
of chemical reactions that produce electricity
and chemical reactions that take place because
electricity is supplied.
electrode The electrode is that solid part of the
electrochemical cell that conducts the electrons
that are involved in the redox reaction.
electrode compartment The solutions in which the
electrodes are immersed are called the electrode
compartments.
electrolysis Electrolysis is a reaction in which elec-
tricity is used to decompose a compound.
electrolyte An electrolyte is a substance that, when
dissolved in solution or melted, conducts an elec-
trical current.electrolytic cells Electrolytic cells use electricity
from an external source to produce a desired
redox reaction.
electromagnetic spectrum The electromagnetic
spectrum is radiant energy, composed of gamma
rays, X-rays, ultraviolet light, visible light, etc.
electron affinity The electron affinity is the energy
change that results from adding an electron to an
atom or ion.
electron capture Electron capture is a radioactive
decay mode that involves the capturing of an
electron from the energy level closest to the
nucleus (1s) by a proton in the nucleus.
electron cloud The electron cloud is a volume of
space in which the probability of finding the elec-
tron is high.
electronegativity The electronegativity (EN) is
a measure of the attractive force that an atom
exerts on a bonding pair of electrons.
electronic configuration The electronic configura-
tion is a condensed way of representing the pat-
tern of electrons in an atom.
elementary step Elementary steps are the indi-
vidual reactions in the reaction mechanism or
pathway.
empirical formula The empirical formula is a chemi-
cal formula that tells us which elements are present
in the compound and the simplest whole-number
ratio of elements.
endothermic Endothermic reactions absorb energy
from their surroundings.
endpoint The endpoint of a titration is the point
signaled by the indication that an equivalent
amount of base has been added to the acid
sample, or vice versa.
enthalpy The enthalpy change, DH, is the heat
gained or lost by the system during constant
pressure conditions.
entropy Entropy (S) is a measure of the disorder of
a system.
equilibrium constant The quantity calculated when
the equilibrium concentrations of the chemical
species are substituted into the reaction quotient.
equivalence point The equivalence point is that
point in the titration where the moles of H+ in the
acid solution have been exactly neutralized with
the same number of moles of OH-.
excited state An excited state of an atom is an
energy state of higher energy.
exothermic An exothermic reaction releases energy
(heat) to its surroundings.22-Moore_APP_p371-412.indd 386 31/05/18 1:59 pm