LO 54 - 58 Flashcards
_________ acids typically ionize in __________ steps each with their own ____ value
polyprotic
successive
Ka
Ka 1 is always _______ Ka 2 in polyprotic acids
>
Why is Ka 1 bigger than Ka 2 for polyprotic acids?
Because the Ka 1 is separation from a neutral molecule while the Ka 2 is separation from an anion
Lewis acids act as electron pair ________
acceptors
Lewis bases act as electron pair ________
donors
A substance does not need to contain H to be an acid under the _________ definition
Lewis
The product of a Lewis acid-base reaction is known as an ________
adduct
What kinds of molecules act as Lewis acids?
- molecules with incomplete octets
- molecules with multiple possible e configurations
- cations
Why can’t you drink antifreeze?
Affects blood acidity if buffers are overwhelmed resulting in acidosis
_______ resist pH change via neutralization
Buffers
What is needed to make a buffer solution?
Weak acid and its conjugate base
Weak base and its conjugate acid
What neutralizes added base in a buffer solution?
the weak acid
What is the common ion effect?
2 solutions sharing a common ion (i.e. an acid/base and associated conjugate) will result in decreased ionization
What is the Henderson-Hasselbach equation used for?
Relates the pH of a buffer solution to the concentrations of buffer components
What is the formula for the Henderson-Hasselbach equation?
What is the first step in calculating pH change for a buffer solution?
The stoichiometric calculation in which the limiting reactant is identified and used (in mols) to determine the changes in mols for the reactants and products
After determining change in mols, what is the second step in calculating pH change for a buffer solution?
Use a RICE table to find the equilibrium concentrations for the new pH from a given or determined Ka
Adding a small amount of strong acid to a buffer converts ______________ –> _____________
a stoichiometric amount of the base –> the conjugate acid
Adding a small amount of strong acid to a buffer _________ the buffer pH
decreases
Adding a small amount of strong base to a buffer converts ______________ –> _____________
a stoichiometric amount of the acid –> the conjugate base
Adding a small amount of strong base to a buffer _________ the buffer pH
increases
An _________ buffer neutralizes small to moderate amounts of added acid or base
effective
A buffer is most effective when . . .
concentrations of acid and conjugate base are high and equal
In order for a buffer to remain effective, concentrations of acid and conjugate base should NOT differ by more than a factor of ___________
10
A concentrated buffer contains more WA and Con. Base than a weak buffer and therefore can neutralize ___________ added acid or base
more
The effective range for a buffering system is . . .
one pH unit from either side of the pKa
What is the equation to find the effective range for a buffering system?
pH = pKa +/- 1
Increasing the absolute concentration of buffer components, ________ buffer capacity
increases
The smaller the difference in buffer component concentrations, _________ the overall buffer capacity
increases
______________ is the ability to neutralize added acid AND added base
overall buffer capacity
