Acid and Bases (10)

Question 1

Arrhenius acid and base

Answer 1

Arrhenius acid will dissociate to form an excess of H+ in the solution.

The Arrhenius base will dissociate to form an excess of OH- in solution.

Question 2

Bronsted-Lowry Acid

Answer 2

Bronsted-Lowry acid is a species that donates hydrogen ions (H+)

The bronsted-Lowry base is a species that accepts hydrogen ions (H+)

Water is a bronsted-lowry acid b/c it can donate a proton to other species.

Question 3

Lewis acid-base

Answer 3

Lewis acid: electron pair acceptor

Lewis base: electron-pair donor

Question 4

Bronsted lowry vs. Lewis acid base

Answer 4

Bronsted Lowry definition revolves around protons (H+)

Lewis definition of electrons

Question 5

Acid naming:

Answer 5

If anion ends in -ite (less oxygen) , then acid will end with -ous acid

If anion ends in -ate (more oxygen), then acid will end with -ic acid

Question 6

Water dissociation constant Kw

Answer 6

H2O + H2O ⇌ H3O+ + OH-

Kw = [H3O+] [OH-] = 1.0 x 10^-14

The equilibrium constant is dependent on temperature. Therefore, isolated changes in concentration, pressure, or volume will not affect Kw.

Question 7

pH vs pOH

Answer 7

pH = -log [H+] = log 1/[H+]

pOH = -log[OH-] = log 1/[OH-]

pH + pOH = 14

Question 8

pH condition

Answer 8

pH = 7 = neutral ONLY valid at 25°C (298K)

Question 9

Strong acids and base

Answer 9

completely dissociate into their component ions in an aqueous solution.

NaOH –> Na+ + OH-

Question 10

Strong acids

Answer 10

HCl (hydrochloric acid), HBr (hydrobromic acid), HI (hydroiodic acid), H2SO4 (sulfuric acid), HNO3 (nitric acid), and HClO4 (perchloric acid)

Question 11

Strong base

Answer 11

NaOH (sodium hydroxide) , KOH (potassium hydroxide) , and other soluble hydroxides of Group IA metals.

Question 12

Weak acids and base

Answer 12

partially dissociate in aqueous solution

Question 13

Ka acid dissociation constant

Answer 13

the lower the Ka, the weaker the acid, the less it will dissociate

Question 14

Kb base dissociation constant

Answer 14

the lower the Kb, the weaker the base, the less it will dissociate.

Question 15

Kw, Ka, Kb

Answer 15

Ka x Kconjugate base = Kw

Kb x Kconjugate acid = Kw

Kw = 1.0 x 10^-14

Question 16

acid equivalent vs. base equivalent

Answer 16

acid equivalent: equal to one mole of H+ (or more properly H3O+)

base equivalent: equal to one mole of OH-

Question 17

Equivalence point

Answer 17

number of equivalents of acid and base are equal.

NaVa = NbVb

N = normality
V = volume

Question 18

pH of equivalence points

Answer 18

• Strong acid + weak base –> equivalence point pH < 7
• Strong acid + strong base –> equivalence point pH = 7
• Weak acid + strong base –> equivalence point pH > 7

Question 19

Buffer System

Answer 19

weak acid + conjugate salt

weak base + conjugate salt

Question 20

Buffer Capacity

Answer 20

The ability of a buffer to resist changes in pH. Maximum

buffering capacity is within 1 pH point of the pKa.

Question 21

Half-equivalence point

Answer 21

center of the buffer region.

When [A-] = [HA] at the half equivalence point, log(1) = 0, so pH = pKa

Question 22

Henderson- Hasselbalch equation

Answer 22

pH = pKa + log [A-] / [HA]

pOH = pKb + log [B+] / [BOH]