Aqueous Ionic Equilibrium Flashcards
Acidosis:
a conditions in which the acid affects the equilibrium between hemoglobin and oxygen
A buffer resists:
pH change
How does a buffer resist pH change
it neutralizes added acid or added base
a buffer contains
significant amounts of weak acid/weak base and its conjugate base/acid
in a buffer, the acid does what
neutralizes added base
common ion affect
tendency for a common ion to decrease the solubility of an ionic compound or to decrease the ionization of a weak acid or base
why is “x is small” approximation valid
so little of a weak acid ionizes compared to its initial concentration
in a solution in which acid and conjugate base concentrations are equal, [H3O+] is equal to what?
Ka
Henderson-Hasselbalch equation:
pH=pKa+log([bas]/[acid])
the pH of a buffer increases with an increase in…
in the amount of base relative to the amount of acid
Henderson-Hasselbalch equation only works if:
the x is small approximation is valid
x is small approximation applies when what 2 things are true
1) the initial concentrations of acids (and/or bases) are not too dilute
2) the equilibrium constant is fairly small
for x is small approximations, initial concentrations of acids and conjugate bases should be at least how much greater than the equilibrium constant?
10^2-10^3
calculating the pH of buffer solution requires breaking the problem into what 2 parts:
1) stoich calculation
2) equilibrium calculation
in a single buffer solution, BLANK is the same for boht the acid and the base
volume
adding a small amount of strong acid to a buffer converts a stoichiometric amount of the base to the conjugate acid and does what to the pH of the buffer?
decreases the pH of the buffer (adding acid decreases the pH)
adding a small amount of strong base to a buffer converts a stoichiometric amount of the acid to the conjugate base and does what to the pH?
increases the pH of the buffer (adding base increases the pH)
adding acid creates more BLANK, adding base creates more BLANK
acid, base
capacity of buffer:
how much added acid or base it can effectively neutralize
range of a buffer
the pH range over which a particular acid and its conjugate base can be effective
when is a buffer most effective? (in terms of relative concentrations)
when concentrations of acid and conjugate base are equal
For a buffer to be reasonably effective, relative concentrations of acid and conjugate base should not differ by..
more than a factor of 10
when can be said of a buffer solution when concentrations of acids and bases are high?
the buffer is effective
the more dilute the buffer components..
the less effective the buffer
the lowest pH for an effective buffer occurs when?
the base is one tenth as concentrated as the acid
the highest pH for an effective buffer occurs when?
the base is ten times as concentrated as a acid
what would be an effective buffering range system for a weak acid with pKa of 5.0?
4.0-6.0
buffer capacity increases with:
increasing absolute concentrations of buffer components
Equivalence point
the point in the titration when the number of moles of base is stoichiometrically equal to the number of moles of acid; neither reactant is in excess
when titrating a weak acid with a strong base, between the initial pH and the equivalence point, what happens to the solution?
it becomes a buffer
for the titration of a weak acid with strong base, what occurs at exactly the half-way equivalence point?
pH=pKa
for the titration of weak acid with strong base, what happens at the equivalence point?
the acid has been converted into its conjugate base
what is Ksp
the measure of the solubility of a compound
what is molar solubility?
solubility in units of moles per liter
True/False: Ksp is the molar solubility
FALSE: Ksp is the solubility product constant
True/False: Ksp is dependent on temperature
true
true/false: solubility depends on the kind of solution
true
relationship between Ksp nd molar solubility depends on:
the stoichiometry of the dissociation reaction
the solubility of an ionic compound is BLANK in a solution containing a common ion than in pure water
lower
if pH is high, the rxn will shift:
left
if pH is low, rxn will shift:
right
the solubility of an ionic compound with a strongly basic or weakly basic anion BLANK with increasing acidity
increases
BLANK, BLANK, and BBLANK are more soluble in acidic water than in pure water
hydroxides, sulfides, and carbonates
what is the differemce between Q and Ksp
is the value of this product at equilibrium only, whereas Q is the value of the product under any conditions
If more solid is added to an unsaturated solution, what will happen?
it will dissolve
Selective Precipitation:
a process involving the addition of a reagent that forms a precipitate with one of the dissolved cations but not the others
The difference in values required for selective precipitation is:
at least 10^3
what can selective precipitation be used for?
to determine which metal ions are present in an unknown solution
Qualitative analysis involves:
finding the kind of ions present in the solution
quantitative analysis:
amounts of substances in a solution or mixture.
Transition metal ions tend to be good
electron acceptors (Lewis acid)
complex ion:
ontains a central metal ion bound to one or more ligands
ligand:
neutral molecule or ion that acts as a Lewis base with the central metal ion
formation constant (Kf) :
The equilibrium constant associated with the reaction for the formation of a complex ion
if Kf is large, then:
formation of the complex ion is highly favored
the solubility of an ionic compound containing a metal cation that forms complex ions BLANK in the presence of Lewis bases that complex with the cation
increases
what are the most common Lewis bases that increase the solubility of metal cations?
NH3, CN-, OH-
why do metal hydroxides become more soluble in acidic solutions?
they can act as bases and react with H3O+
The ability of an amphoteric metal hydroxide to act as an acid does what to its solubility in basic solution?
increases
