ch 17 aqueous equilibrium

common-ion effect

when a weak electrolyte is combined with a strong electrolyte that contains a common ion, the ionization of the weak electrolyte is surpressed

buffer solution

a solution consisting of weak acid and its conjugate base(or a weak base and its conjugate acid) that resists change in pH

Henderson- Hasselbach equation

pH= pKa+ log [base]/[acid]

buffer capacity

the ability of the buffer solution to resist a change in pH when an acid or base is added

titrant

a solution of a known concentration

analyte

a solution of an unknown concentration

titration curve

a plot of pH versus volume of titrant added over the course of a titration

Strong acid with Strong base titration

A- initial pH acid; pH= -log[H3O+]

B- some titrant added, but EP not reached

C- Equivalence point, mols of acid=mols base, pH=7

D-all acid neutralized and titrant in excess; pOh calculated from excess OH- in solution

Strong base titrated with strong acid

A-initial pH of solution

B-some titrant added, but EP not reached

C-Equivalence point, mols of acid=mols base, pH=7

D-all base neutralized and titrant in acid; pH calculated from excess H+ in solution

BAA table

B- before the titration

A- additional mols acid/base

A-after mols

Weak acid-strong base titration

initial pH of weak acid is higher than that of a strong acid

displays less abrupt pH change near the EP then SA/SB

pH at equivalence point is greater than 7

weak base- strong acid titration

initial pH of weak base is lower than a strong base

pH at EP is less than 7

pH at the half-equivalence point is equal to pKa of the conjugate acid of weak base titrated

endpoint

the color change of the indicator in a titration

solubility

the amount of a substance that is dissolved in a saturated solution of that substance

molar solubility

the number of moles of a substance that can dissolve into 1L of solution