Answers to Chapter 18 and 19 Review Sheet
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14.
15.
0 to 14
0 to 7
7 to 14
7
Weak acids have higher pH’s than strong acids. Strong acids have pH’s around 0-2.
Weak acids have pH’s around 3-6. Strong bases have higher pH’s than weak bases.
Strong bases have pH’s around 12-14. Weak bases have pH’s around 8-11. Whether the
substance is an acid or a base, the weaker it is, the closer it is to pH 7.
Acids are substances whose formulas begin with “H.” Acid is in the name of the acid.
Common household substances that are acids are lemon juice, tomato juice, and vinegar.
Anything with “hydroxide” is a base as well as any substance that is a proton acceptor. A
common household base is ammonia whose formula is NH3.
Acids taste sour and bases taste bitter.
Phenolphthalein and litmus are indicators.
Phenolphthalein is colorless in acidic solutions and pink in basic solutions. Since
ammonia is a base, the resulting solution of ammonia and phenolphthalein will be pink.
Litmus is a test strip that is red when dipped in acidic solutions and blue when dipped in
basic solutions. Since tomato juice is an acid, the litmus test strip will be red when
dipped in tomato juice.
The decreasing order of reactivity of the following metals with hydrochloric acid is:
magnesium, zinc, iron, copper
Zn + 2 HCl  H2 + ZnCl2
H3O+1
Acidic: tomato juice, lemon juice, vinegar. Neutral: Milk. Basic: ammonia
H2S (aq) + 2 H2O (ℓ)
Ka = [H3O+1]2 [S2]
 2 H3O+1 (aq) + S2(aq)
[H2S]
16.
Fe(OH)3 (aq)  Fe+3 (aq) + 3 OH1 (aq)
Kb = [Fe+3] [OH1]3
[Fe(OH)3]
17.
C5H5N (aq) + H2O (ℓ)  C5H5NH+1 (aq) + OH1 (aq)
base
acid
conjugate acid
conjugate base
Kb = [C5H5NH+1] [OH1]
[C5H5N]
18.
HClO4 (aq) + H2O (ℓ)
acid
base

ClO41(aq) + H3O+1 (aq)
conjugate base
conjugate acid
Ka = [H3O+1] [ClO41]
[HClO4]
19.
20.
21.
An Arrhenius acid must have hydrogen ions as the only positive ions in water solution
and an Arrhenius base must have hydroxide ions as the only negative ions in water
solution. A Brønsted-Lowry acid is a proton donor and a Brønsted-Lowry base is a
proton acceptor.
Neutralization reaction
[H2CO3] = 0.036 M, so [H+1] = 0.072 M
pH =  log [H+1]
pH =  log [0.072]
pH = 1.14
22.
[H2C2O4] = 0.037 M, so [H+1] = 0.074 M
pH =  log [H+1]
pH =  log [0.074]
pH = 1.13
pH + pOH = 14
1.13 + pOH = 14
pOH = 12.87
23.
pH + pOH = 14
pH + 4.32 = 14
pH = 9.68
pH =  log [H+1]
9.68 =  log [H+1]
2.1 x 1010 M = [H+1]
24.
Strong acid-strong base titration curve
14
pH
7
0
Increasing Volume
Weak acid-strong base titration curve
14
pH
7
0
Increasing Volume
Strong acid-weak base titration curve
14
pH
7
0
Increasing Volume
25.
HCl (aq) + NH3 (aq) 
0.250 M
xM
85.0 mL
20.0 mL
NH4+1 (aq) + Cl1 (aq)
Since the ratio between the acid and the base is 1:1, use MV = MV
MV = MV
(0.250 M)(0.085 L) = (x M) (0.020 L)
1.06 M = Molarity of NH3
26.
4 HClO3 (aq) + Mn(OH)4 (aq) 
0.10 M
xM
89 mL
50. mL
Mn(ClO3)4 (aq) + 4 H2O (ℓ)
Since the ratio between the acid and the base is 4:1, use dimensional analysis.
1 mol Mn(OH)4 0.10 mol HClO3
4 mol HClO3
1 L HClO3
27.
4 HClO3 (aq) + Mn(OH)4 (aq) 
0.25 M
0.10 M
65 mL
x mL
0.089 L HClO3
0.050 L Mn(OH)4
=
0.045 M Mn(OH)4
Mn(ClO3)4 (aq) + 4 H2O (ℓ)
Since the ratio between the acid and the base is 4:1, use dimensional analysis.
103 mL Mn(OH)4 1 L Mn(OH)4
1 mol Mn(OH)4 0.25 mol HClO3 0.065 L HClO3 =
1 L Mn(OH)4
0.10 mol Mn(OH)4 4 mol HClO3
1 L HClO3
= 41 mL Mn(OH)4