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Chemistry 2e

Key Terms

Chemistry 2eKey Terms

Key Terms

acid ionization
reaction involving the transfer of a proton from an acid to water, yielding hydronium ions and the conjugate base of the acid
acid ionization constant (Ka)
equilibrium constant for an acid ionization reaction
acid-base indicator
weak acid or base whose conjugate partner imparts a different solution color; used in visual assessments of solution pH
acidic
a solution in which [H3O+] > [OH−]
amphiprotic
species that may either donate or accept a proton in a Brønsted-Lowry acid-base reaction
amphoteric
species that can act as either an acid or a base
autoionization
reaction between identical species yielding ionic products; for water, this reaction involves transfer of protons to yield hydronium and hydroxide ions
base ionization
reaction involving the transfer of a proton from water to a base, yielding hydroxide ions and the conjugate acid of the base
base ionization constant (Kb)
equilibrium constant for a base ionization reaction
basic
a solution in which [H3O+] < [OH−]
Brønsted-Lowry acid
proton donor
Brønsted-Lowry base
proton acceptor
buffer
mixture of appreciable amounts of a weak acid-base pair. The pH of a buffer resists change when small amounts of acid or base are added
buffer capacity
amount of an acid or base that can be added to a volume of a buffer solution before its pH changes significantly (usually by one pH unit)
color-change interval
range in pH over which the color change of an indicator is observed
conjugate acid
substance formed when a base gains a proton
conjugate base
substance formed when an acid loses a proton
diprotic acid
acid containing two ionizable hydrogen atoms per molecule
diprotic base
base capable of accepting two protons
Henderson-Hasselbalch equation
logarithmic version of the acid ionization constant expression, conveniently formatted for calculating the pH of buffer solutions
ion-product constant for water (Kw)
equilibrium constant for the autoionization of water
leveling effect
observation that acid-base strength of solutes in a given solvent is limited to that of the solvent’s characteristic acid and base species (in water, hydronium and hydroxide ions, respectively)
monoprotic acid
acid containing one ionizable hydrogen atom per molecule
neutral
describes a solution in which [H3O+] = [OH−]
oxyacid
ternary compound with acidic properties, molecules of which contain a central nonmetallic atom bonded to one or more O atoms, at least one of which is bonded to an ionizable H atom
percent ionization
ratio of the concentration of ionized acid to initial acid concentration expressed as a percentage
pH
logarithmic measure of the concentration of hydronium ions in a solution
pOH
logarithmic measure of the concentration of hydroxide ions in a solution
stepwise ionization
process in which a polyprotic acid is ionized by losing protons sequentially
titration curve
plot of some sample property (such as pH) versus volume of added titrant
triprotic acid
acid that contains three ionizable hydrogen atoms per molecule
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