Analytical Exam 1

Front 1

strong acid/base

Back 1

those that are completely dissociated (to H+ or OH-) in water

Front 2

fraction of association(acid) or dissociation (base)

Back 2

the fraction of acid/base in the form A-/BH+

Front 3

Henderson-Haselbalch equation

Back 3

a logarithmic rearranged form of the acid dissociation equlibrium equation: ph = pK + log[A-]/[HA]

Front 4

pK

Back 4

the negative logarithm of an equilibrium constant: pK = -logK

Front 5

weak acid/base

Back 5

has a weak dissociation constant and therefore does not go to completion

Front 6

base hydrolysis constant, Kb

Back 6

the equilibrium constant for the reaction of a base, B, with H2O

Front 7

conjugate acid-base pair

Back 7

an acid and a base that differ only through the gain or loss of a single proton

Front 8

acid dissociation constant, Ka

Back 8

equilibrium constant for the reaction of an acid, HA, with H2O

Front 9

buffer

Back 9

a mixture of a weak acid and its conjugate base; resists canges in ph when acids or bases are added

Front 10

buffer capacity

Back 10

a measure of the ability of a buffer to resist changes in pH; larger capacity, greater resistance

Front 11

weak electrolyte

Back 11

one that only partly dissociates into ions when it dissolves

Front 12

amino acid

Back 12

one of 20 building blocks of proteins, having the general structure R
|
H3NCCO2-
where R is different substituent for each acid

Front 13

amphiprotic

Back 13

one that can act as both a proton donor and a proton acceptor; intermediate species of polyprotic acids are amphiprotic

Front 14

diprotic acids/bases

Back 14

compounds that can donate or accept 2 protons

Front 15

hydrolysis

Back 15

"reaction with water"; the reaction B + H2O -> BH+ + OH- is hydrolysis of a base

Front 16

isoelectric focusing

Back 16

a technique in which a sample containing polyprotic molecules is subjected to a strong electric field in a medium with a pH gradient. Each species migrates until it reaches the region of its isoelectric pH. IN that region, the molecule has no net charge, ceases to migrate, and remains focused in a narrow band.

Front 17

isoelectric point

Back 17

that pH at which the average charge of a polyprotic species is 0. SAME AS ISOELECTRIC pH

Front 18

isoionic point

Back 18

the pH of a pure solution of a neutral, polyprotic molecule. The only ions present are H+, OH-, and those derived from the polyprotic species. SAME AS ISOIONIC pH

Front 19

polyprotic acids/bases

Back 19

compound that can donate or accept more than one proton

Front 20

speciation

Back 20

describes the distribution of an element or compound among different chemical forms

Front 21

zwitterion

Back 21

a molecule with a positive charge localized at one position and a negative charge localized at another position

Front 22

gran plot

Back 22

a graph such as the plot of Vb * 10^-pH versus Vb used to find the end point of a titration. Vb is the volume of base (titrant) added to an acid being titrated. The slope of the linear portion of the graph is related to the dissociation constant of the acid

Front 23

indicator

Back 23

a compound having a physical property that changes abruptly near the equivalence point of a chemical reaction

Front 24

indicator error

Back 24

difference between the indicator end point of a titration and the true equivalence point

Front 25

transition range

Back 25

for an acid=base indicator, the pH range over wihch the color change occurs. for a redox indicator, the potential range over which the color change occurs.