CHEM 1B: Acid Base Equilibria

Strong acids

HCl, HBr, HI, H2SO4, HNO3, HClO4

Strong bases

NaOH, KOH, LiOH, Ba(OH)2

Strong acids/bases __ dissociate, while weak acids/bases __ dissociate.

completely (not equilibrium), partially (equilibrium)

Conjugate base or acid

the ions of weak acid/base

Buffer

weak acid with its conj. base, weak base with its conj. acid

pH formula

pH = -log[H+]

pOH formula

pOH = -log[OH-]

pH + pOH =

14

% dissociation

([conc. of dissociated] / [initial conc.]) x 100%

if only one cmpd. is given, what do you need to identify?

if the cmpd. is strong, weak, or conjugate

if the one cmpd. is strong, what kind of problem is it?

dissociates quickly, so not equilibrium problem

if the one cmpd. is weak, what kind of problem is it?

equilibrium problem (add water) and use Ka or Kb

if the one cmpd. is conjugate, what kind of problem is it?

equilibrium problem (add water) and use Kh = Kw/ Ka or Kb

if two cmpds. are given, what do you need to identify?

if one is an acid and the other is a base

if not given an acid and base, and one of the cmpds. is strong and the other is weak, what kind of problem is it?

strong cmpd. always wins, so not an equilibrium problem

if give an acid and base, and they are not a matching pair, what kind of problem is it?

a limiting reagent problem:

1) use ICF to find limiting reagent with moles

2) use cmpds. leftover from ICF in ICE to find equilibrium with molarity

if give an acid and base, and they are a matching pair, what kind of problem is it?

a buffer equilibrium problem

1) the cmpds. dissociate into ions

2) use ICE to solve for Ka/Kb