Acids and Bases

Question 1

Strong Acid/Base Concentrations

Answer 1

High-greater than 10^-6. Low-less than 10^-8. Intermediate-between 10^-6 and 10^-8

Question 2

Formal Concentration

Answer 2

concentration before dissociation/association of a species

Question 3

Fraction of Dissociation

Answer 3

how much of the acid forms the conjugate base (x/F)

Question 4

Fraction of Association

Answer 4

fraction of base forming the conjugate acid (x/F)

Question 5

Buffer

Answer 5

• solution that resists changes in pH
• mix of comparable amounts of conjugate acid/base pair
• depends on ionic strength and temperature

Question 6

Using Buffers

Answer 6

• work best in +/- 1 range

- Henderson-Hasselbalch equation

Question 7

Buffer Capacity

Answer 7

• measure of how well a solution resists pH change

- max capacity is when the pKa = pH

Question 8

Preparing a Buffer

Answer 8

1. Weight out acid/base and dissolve in water
2. Put on pH meter and adjust to desired pH with acid/base
3. Transfer to volumetric flask and dilute

Question 9

Amino Acids

Answer 9

• bond to from peptide bonds

- are polyprotic systems

Question 10

Polyprotic Acid/Base

Answer 10

acid/base that can give/accept more than one proton

Question 11

Polyprotic Kw Relationships

Answer 11

Conjugate pairs multiply to equal Kw

Question 12

Isoionic Point

Answer 12

pH obtained when the pure, neutral polyprotic acid (HA) is dissolved in water

Question 13

Isoelectric Point

Answer 13

pH at which the average charge of the polyprotic acid is zero

Question 14

Diprotic Buffers

Answer 14

• still use H-H equation

- uses the ratio of the conjugate base to acid pair

Question 15

Principal Species

Answer 15

• when pH = pKa there’s a 50/50 mix
• if not equal: prinicpal is the one the pH “falls in”
• use chart

Question 16

Fractional Comp. Equations

Answer 16

• fraction of x/F
• at pKa 50:50 mix
• acid form preferred at low pH
• base form preferred at high pH