Exam 4 Flashcards
does a cation that’s part of a strong base affect the pH?
nah
common-ion effect
shift in position of equilibrium caused by the addition of an ion
the lower the pKa…
the higher the pH
pH buffer
solution of a weak acid and its conjugate base that is resistant to pH changes
buffer range
pH range within which a given buffer can provide ph protection
to make a buffer:
1) pick acid whose pKa is the pH you want +-1
2) determine the base to acid ratio you need to get the target pH
buffer capacity
quantity of acid/base that a buffer can neutralize while maintaining pH within desired range
pH indicators
water-soluble and weak organic acids that change color as the pH changes
what’s a buffer solution usually made up of?
weak acid and its conjugate base
decrease in H+ does what to the pH?
raises it (shifts reaction to the left)
when can you apply the common-ion affect?
any equilibrium involving a weak acid and its conjugate base
pKb+pKa=
14
equivalence point
equal # of moles of acid and base
alkalinity titration
buffer capacity of a solution against addition of acid
why is an alkalinity titration more complex?
it has 2 equivalence points
pH at equivalence point in the titration of a weak acid with a strong base?
> 7
Ksp
solubility product
molar solubility
amount of dissolved solute expressed as mol/L
molar solubility symbol
S
higher solubility when
at higher temp
solubility product constant
Ksp
1/2 way to the equivalence point, what does the pH equal?
the pKa
what is solubility measured in?
g/L or mg/L
when is the solubility higher?
at a higher temp
for insoluble salts that contain basic anions, what happens to the solubility as the pH decreases?
solubility increases
Q>K
precipitate forms
Q < K
dissolves (no precipitate)
the lower the pKa value…
the stronger the acid
