Chapter 17 - Additional Aspects of Aqueous Equilibrium

common-ion effect

the solubility of weak electrolytes will decrease when a soluble compound containing a common ion is added to solution

buffers

solution of a weak conjugate acid-base pair (HA/A-) that resist changes in pH when strong acids or based are added (differ by one hydrogen)

henderson-hasselbalch equation (H-H equation)

can calculate pH of a buffer if Ka and ratio of conjugate acid to base is known (when concentrations and Ka are similar in magnitude, equation will fail)

buffer capacity

the amount of acid or base that a buffer can neutralize before the pH changes appreciably (determined by [HA] and [A-]

pH range

buffers typically have a range within + or - 1 pH unit of the pKa

titrant

reactant being slowly added whose concentration is known

analyte

reactant being studied whose pH is monitored; sometimes concentration is unknown

titration curve

graph of solution pH vs. volume of titrant added

equivalence point

the pH at which the moles of titrant equals the moles of analyte

indicators

weak acids that differ in color from conjugate base