Types of Chemical Reactions and
Solution Stoichiometry
Chapter 4
1
Section 4.1
Water, the Common
Solvent
2
Nature of Water
• Type of bond?
• Shape?
• Polarity?
Covalent
Bent/Angular
Polar
3
Ionic Solute-Solvent Interaction
• Ionic solids that dissolve are soluble.
• Ionic solids will dissolve in polar solvents but
not nonpolar solvents
• Water molecules break the crystal lattice into
separate ions. This is dissociation.
• Then the water molecules surround the ions.
This is hydration.
• Ionic solids that do not dissolve are insoluble.
4
Ionic Solute-Solvent Interaction
p. 411
5
Solubility of Compounds
notes
6
Solubility of Compounds
notes
7
Liquid Solute-Solvent Interaction
• Miscible – Liquids that dissolve freely in one
another in any proportion.
• Immiscible – Liquids that are not soluble in
each other.
• “Likes dissolve likes”
Polar solutes dissolve in polar solvents.
Nonpolar solutes dissolve in nonpolar
solvents.
• Alcohols are slightly polar.
8
Miscible and Immiscible
9
Immiscible & Miscible
p. 412
10
Section 4.2
The Nature of Aqueous
Solutions
11
Solution
• A homogeneous mixture of two or more
substances in a single phase
• Particles are thoroughly mixed and remains
mixed indefinitely
• Components of a solution
– Solvent: does the dissolving; the larger
amount
– Solute: is being dissolved; the smaller
amount
12
Electric Conductivity in Solutions
p. 406
13
Electrolytes & Nonelectrolytes
• Electrolyte – a substance that dissolves in
water to give a solution that conducts electric
current
• Nonelectrolytes
– a substance that dissolves in water to give a
solution that does not conduct electricity
– Does not produce ions
– Example: sugar and ethanol
14
Strong Electrolytes
• Completely ionized when they are dissolved in
water
• Three classes
– Soluble Salts
NaCl (s)  Na1+(aq) + Cl1-(aq)
– Strong Acids: produce H+ ions when dissolved in
water
• HCl (g) + H2O (l)  H3O+ (aq) + Cl- (aq)
– Strong Bases: produce OH- ions when dissolved in
water
• NaOH (s)  Na+ (aq) + OH- (aq)
15
Strong Acids
 An acid that ionizes completely in aqueous
solution.
 STRONG ACID LIST
HCl
hydrochloric acid
HI
hydroiodic acid
HBr
hydrobromic acid
H2SO4
sulfuric acid
HNO3
nitric acid
HClO3
chloric acid
HClO4
perchloric acid
16
Strong Bases
 Strong Bases – bases that dissociate
completely – strong electrolytes
 Formed from Group I & II metals
combined with hydroxide
17
Weak Electrolytes
• Substances that exhibit a small degree of
ionization in water
• Two classes
– Weak Acids: produce few H+ ions when dissolved
in water
CH3COOH(aq) + H2O(l)  CH3COO-(aq) + H3O+(aq)
– Weak Bases: produce few OH- ions when
dissolved in water
NH3 (aq) + H2O (l)  NH4+ (aq) + OH-(aq)
18
Section 4.3
The Composition of
Solutions
19
Molarity
The number of moles of solute in one liter of
solution.
M
moles of solute
=
liters of solution
M
mol
=
L
20
Molarity Practice Problems
1. Calculate the molarity of a solution prepared
by dissolving 11.5 g of solid NaOH in enough
water to make 1.50 L of solution.
2. Give the concentrations of each type of ion in
the following solutions:
a. 0.50 M Co(NO3)2
b. 1 M Fe(ClO4)3
3. Calculate the number of moles of chloride
ions in 1.75 L of 1.0 x 10-3 M ZnCl2.
4. Typical blood serum is about 0.14 M NaCl.
What volume of blood contains 1.0 mg NaCl?
21
Standard Solution
•
A solution whose concentration is accurately
known.
– To analyze the alcohol content of a certain wine,
a chemist needs 1.00 L of an aqueous 0.200 M
K2Cr2O7 solution. How much solid potassium
dichromate must be weighed out to make this
solution?
22
Dilution
•
•
•
A solution in concentrated form.
Dilution: process where water is added to
achieve the molarity desired for a particular
solution.
If the mole ratio is 1:1, then M1V1=M2V2 can
be used
– What volume of 16 M sulfuric acid must be used
to prepare 1.5 L of a 0.10 M sulfuric acid
solution?
23
Section 4.5
Precipitation Reactions
24
Precipitation Reactions
•
•
•
Two solutions mix and an insoluble solid
forms
The solid that forms is called a precipitate.
Predicting Reaction Products:
– Using the solubility rules, predict what will
happen when the following pairs of solutions are
mixed.
•
•
•
Potassium nitrate and barium chloride
Sodium sulfate and lead (II) nitrate
Potassium hydroxide and iron (III) nitrate
25
Section 4.6
Describing Reactions in
Solution
26
NET IONIC EQUATION
• Write the balanced equation for the reaction
between ammonium sulfide and cadmium II
nitrate. Be sure to include states of matter
• What type of reaction is it? What are the
products?
(NH4)2S
(aq)
+ Cd(NO3)2 (aq) 
2 NH4NO3
(aq)
+ CdS (s)
27
NET IONIC EQUATION
(NH4)2S
(aq)
+ Cd(NO3)2 (aq)  2 NH4NO3
(aq)
+ CdS (s)
Each (aq) is dissociated.
The (s) is not dissociated; it is the precipitate.
28
NET IONIC EQUATION
(NH4)2S
2
+ Cd
Cd(NO
(NO3) 2 (aq)  2 NH44NO3
(aq)
(aq)
+ CdS (s)
1+
2-
2+
1-
1+
1-
(aq)
(aq)
(aq)
(aq)
(aq)
(aq)
+
+
+2
2
+2
+
(s)
Break all (aq) into ions; not the (s)
Balance and add states
29
NET IONIC EQUATION
(NH4)2S
(aq)
+ Cd(NO3)2 (aq)  2 NH4NO3
(aq)
+ CdS (s)
1+
2-
2+
1-
1+
1-
(aq)
(aq)
(aq)
(aq)
(aq)
(aq)
2 (NH4) + S + Cd + 2 (NO3)  2 NH4 + 2 NO3 + CdS
+

Identify spectator ions and remove
Write what’s left.
30
(s)
NET IONIC EQUATION
(NH4)2S
(aq)
1+
2 (NH4) +
+ Cd(NO3)2 (aq)  2 NH4NO3
+ CdS (s)
1-
1+
1-
(aq)
(aq)
(aq)
+ 2 (NO3)  2 NH4 + 2 NO3 +
+
(aq)
Cd
(aq)
2+
(aq)
+
S
2(aq)

CdS
(s)
This is the net ionic equation.
31
Ag(NO3) + NaCl
32
NET IONIC EQUATION
• Write the balanced equation for the reaction
between sodium chloride and silver nitrate. Be
sure to include states of matter
• What type of reaction is it? What are the
products?
NaCl
(aq)+
Ag(NO3) (aq)  NaNO3
(aq)+
AgCl (s)
33
NET IONIC EQUATION
NO3 (aq)  NaNO
NaNO33
NaCl (aq) + Ag
AgNO
1+
1+
1-
+
(aq)
+
(aq)
1-

+
(aq)
(aq)
(aq)
1+
+
(aq)
+ AgCl (s)
1-
+
(s)
(aq)
Break all (aq) into ions; not the (s)
Balance and add states
34
NET IONIC EQUATION
NaCl
(aq)
+ AgNO3 (aq)  NaNO3
1+
1-
(aq)
(aq)
1+
(aq)
+ AgCl (s)
1-
1+
1-
(aq)
(aq)
(aq)
Na + Cl + Ag + NO3  Na + NO3 + AgCl
(aq)
+
(s)

Identify spectator ions and remove
Write what’s left.
35
NET IONIC EQUATION
NaCl
(aq)
1+
Na +
+ AgNO3 (aq)  NaNO3
(aq)
Ag
(aq)
+ AgCl (s)
1-
1+
1-
(aq)
(aq)
(aq)
+ NO3  Na + NO3 +
+
1+
(aq)
+
1-
Cl
(aq)

AgCl
(s)
This is the net ionic equation.
36
Section 4.7
Stoichiometry of
Precipitation Reactions
37
Determining the mass of
product formed
1. When aqueous solutions of sodium sulfate
and lead (II) nitrate are mixed, lead (II)
sulfate precipitates. Calculate the mass of
lead (II) sulfate formed when 1.25 L of
0.0500 M lead (II) nitrate and 2.00 L of
0.0250 M sodium sulfate are mixed.
38
Section 4.8
Acid-Base Reactions
39
Brønsted-Lowry Acid & Base

NH3(aq) + H2O(l)
H
O
N
H
H
A molecule
or ion that is
a proton
acceptor
BASE
H
H
NH4+(aq) + OH-(aq)
+
H
H N H
OH-
H
A molecule
or ion that
is a proton
donor
ACID
40
Neutralization Reactions
ACID + BASE
 SALT + WATER
HCl(aq) + NaOH(aq)  NaCl(aq) + HOH(l)
H++Cl- + Na++OH-  Na++Cl- + HOH
H+ (aq) + OH- (aq)  HOH
(l)
 The reaction of hydronium ions and
hydroxide ions to form water molecules.
41
Neutralization Reactions
ACID + BASE
 SALT + WATER
HC2H3O2 (aq) + KOH(aq)  KC2H3O2(aq) + HOH(l)
HC2H3O2 + K++OH-  K++C2H3O2-1+ HOH
HC2H3O2(aq) + OH- (aq)  HOH
-1
+
C
H
O
(l)
2 3 2 (aq)
 The reaction of hydronium ions and
hydroxide ions to form water molecules.
42
Neutralization Reactions
1. What volume of a 0.100 M HCl solution is
needed to neutralize 25.0 mL of 0.350 M
NaOH?
2. In a certain experiment, 28.0 mL of 0.250 M
HNO3 and 53.0 mL of 0.320 M KOH are
mixed. Calculate the amount of water
formed in the resulting reaction. What is the
concentration of H+ and OH- ions in excess
after the reaction goes to completion.
43
Acid-Base Titration
•
•
•
Delivery from a buret of a measured volume
of a solution of known concentration (the
titrant) into a solution containing the
substance to be analyzed (the analyte)
Equivalence point: the point in a titration
where enough titrant has been added to
react exactly with the analyte
Endpoint: The point where the indicator
actually changes color
44
Neutralization
Titration/Analysis
1. A student weighs out a 1.3009 g sample of
KHC8H4O4 . KHP has one acidic hydrogen.
The student dissolves the KHP in distilled
water, adds phenolpthalein and titrates the
solution with sodium hydroxide to the
endpoint. The difference between the final
and initial buret readings indicates that 41.20
ML of the sodium hydroxide is required to
react exactly with the KHP. Calculate the
concentration of sodium hydroxide.
45
Neutralization
Titration/Analysis
2. An environmental chemist analyzed the
effluent from an industrial process known to
produce the compounds CCl4 and HC7H5O2, a
weak acid with one acidic hydrogen. A
sample of the effluent weighing 0.3518 g
was shaken with water and the resulting
aqueous solution required 10.59 mL of
0.1546 M NaOH for neutralization. Calculate
the mass percent of HC7H5O2 in the original
sample.
46