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what is a buffer
a solution containing considerable parts of a weak acid and it’s conjugate base
how does adding a strong acid or strong base affect the pH of a buffer
it is strongly resistent to changes
what is the pH of a buffer close to
the pKa of the weak acid
do buffers go to equilibrium or completion
completion
the equilibrium constant of a buffer should be _________
very large
what affect to H+ and OH- ions have on the pH of a buffer
very little
with a buffer, what kind of diagram do you use
BCA (before change after)
[HB]/[B-] = what?
mols hb/mols b-
how to calculate pH of a buffer system
H.H equation
what are the two factors that the pH of a buffer depend on?
acid equailibrium constant of the weak acid and the ratio of concentrations/amounts of HB and B- (think H.H equation)
what changes when a buffer system has a strong acid or strong base added to it?
pH changes very slightly, the ratio of mols HB/mols B- changes
what is buffer capacity
the amount of OH- or H+ ions that can be absorbed without a big change in pH
How do you pick an indicator for an acid-base rxn?
pick an indicator with an end point that aligns with the pH of the acids/bases equivilance point
what is the equivilance point?
the point at which reaction is complete, equal amounts of acid and base have reacted
what does it mean if [HIn]/[In-] is >= 10? (in means indicator)
the acid color comes through
what does it mean if [HIn]/[In-] is <= 0.1? (in means indicator)
the base color comes through
what does it mean if [HIn]/[In-] is ~~ 1? (in means indicator)
the color is an intermediate between the two species (I.E. green)
what equation to use to get concentration of indicators?
Ka = [H+][In-]/[HIn]
what happens if [in]~~ [HIn]
the solution will be an intermediate green color
for a methyl red indicator, what color indicates low pH
red
for a methyl red indicator, what color indicates high pH
yellow
for a bromythymol blue indicator, what color indicates low pH
yellow
for a bromythymol blue indicator, what color indicates high pH
blue
for a phenolphthalein indicator, what color indicates low pH
colorless
for a phenolphthalein indicator, what color indicates high pH
bright pink
what does a high Kc indicate about the reaction?
that it goes to completion
on a graph, where is the equivilance point?
the steepest part of the graph
how to tell on a acid-base titration graph if the acid/base is strong or weak
very low initial pH = strong acid
what does it mean if the pH = 7 at the equivilance point
strong acid and strong base are reacting
how to find k for the reverse of a reaction
1/(kb)
what does it mean if on a acid-base titration graph the initial pH is between 2-4
weak acid
what is true on a acid-base titration graph halfway to the equivilance point
pH = pKa
what does it mean if the starting pH in an acid-base titration is 10-12
weak base
what is the net ionic equation for a weak acid in water
HB + H2O >< B- + H3O+
what is the net ionic equation for a weak base in water
B- + H2O <> HB + OH-
what is the net ionic equation for a weak acid and a strong base
HB + OH- => B- + H2O
what is the net ionic equation for a strong acid and a weak base
H+ + B- => HB
what is the net ionic equation for a strong acid and a strong base?
H+ + OH- => H2O
the k value of a weak acid and strong base will be ______
high
the k value of a strong acid and a strong base will be _____
high
what kind of chart do you use if a weak acid is in water
ICE
in an ICE diagram, what should you use?
molarity, -x and +x
in a BCA chart, what should you use?
LF, mols
for a weak base in water, what chart should you use?
ICE
in a weak acid + strong base, what chart should you use?
BCA
for a strong acid + weak base, what chart should you use
BCA
for a strong acid and strong base, what chart should you use?
BCA
Note 
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