LO 54 - 58

Question 1

_________ acids typically ionize in __________ steps each with their own ____ value

Answer 1

polyprotic
successive
Ka

Question 2

Ka 1 is always _______ Ka 2 in polyprotic acids

Answer 2

>

Question 3

Why is Ka 1 bigger than Ka 2 for polyprotic acids?

Answer 3

Because the Ka 1 is separation from a neutral molecule while the Ka 2 is separation from an anion

Question 4

Lewis acids act as electron pair ________

Answer 4

acceptors

Question 5

Lewis bases act as electron pair ________

Answer 5

donors

Question 6

A substance does not need to contain H to be an acid under the _________ definition

Answer 6

Lewis

Question 7

The product of a Lewis acid-base reaction is known as an ________

Answer 7

adduct

Question 8

What kinds of molecules act as Lewis acids?

Answer 8

• molecules with incomplete octets
• molecules with multiple possible e configurations
• cations

Question 9

Why can’t you drink antifreeze?

Answer 9

Affects blood acidity if buffers are overwhelmed resulting in acidosis

Question 10

_______ resist pH change via neutralization

Answer 10

Buffers

Question 11

What is needed to make a buffer solution?

Answer 11

Weak acid and its conjugate base
Weak base and its conjugate acid

Question 12

What neutralizes added base in a buffer solution?

Answer 12

the weak acid

Question 13

What is the common ion effect?

Answer 13

2 solutions sharing a common ion (i.e. an acid/base and associated conjugate) will result in decreased ionization

Question 14

What is the Henderson-Hasselbach equation used for?

Answer 14

Relates the pH of a buffer solution to the concentrations of buffer components

Question 15

What is the formula for the Henderson-Hasselbach equation?

Answer 15

Question 16

What is the first step in calculating pH change for a buffer solution?

Answer 16

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

Question 17

After determining change in mols, what is the second step in calculating pH change for a buffer solution?

Answer 17

Use a RICE table to find the equilibrium concentrations for the new pH from a given or determined Ka

Question 18

Adding a small amount of strong acid to a buffer converts ______________ –> _____________

Answer 18

a stoichiometric amount of the base –> the conjugate acid

Question 19

Adding a small amount of strong acid to a buffer _________ the buffer pH

Answer 19

decreases

Question 20

Adding a small amount of strong base to a buffer converts ______________ –> _____________

Answer 20

a stoichiometric amount of the acid –> the conjugate base

Question 21

Adding a small amount of strong base to a buffer _________ the buffer pH

Answer 21

increases

Question 22

An _________ buffer neutralizes small to moderate amounts of added acid or base

Answer 22

effective

Question 23

A buffer is most effective when . . .

Answer 23

concentrations of acid and conjugate base are high and equal

Question 24

In order for a buffer to remain effective, concentrations of acid and conjugate base should NOT differ by more than a factor of ___________

Answer 24

10

Question 25

A concentrated buffer contains more WA and Con. Base than a weak buffer and therefore can neutralize ___________ added acid or base

Answer 25

more

Question 26

The effective range for a buffering system is . . .

Answer 26

one pH unit from either side of the pKa

Question 27

What is the equation to find the effective range for a buffering system?

Answer 27

pH = pKa +/- 1

Question 28

Increasing the absolute concentration of buffer components, ________ buffer capacity

Answer 28

increases

Question 29

The smaller the difference in buffer component concentrations, _________ the overall buffer capacity

Answer 29

increases

Question 30

______________ is the ability to neutralize added acid AND added base

Answer 30

overall buffer capacity