1
Chapter 11 TYPES OF CHEMICAL
REACTIONS
Chapter 20 Predicting the Products of a
Chemical Reaction
2
3
I can …….
• classify reactions:
• double replacement
oPrecipitation
oAcid / base
•predict and write the products of the above types of reactions.
•predict the states of the reactants by using the solubility rules.
•identity spectator ions and explain what they do.
4
Double Replacement Reactions
Reactants are always 2 compounds
Products are always 2 new compounds
The same charge ions switch partners
We do not just “switch” the cations
(metals) to create the products.
NaCl + BaO → NaO + BaCl
5
is not correct !!
You must make sure you follow the rules of formula writing
when writing new compounds:

1.
2.
3.
4.
Predict what is formed in the reaction
Check the charges of each ion
Criss-cross and drop charges to write correct
chemical formulas
Balance the final equation using coefficients
Examples:
1. Predict what is formed in the reaction
2. Check the charges of each ion
3. Criss-cross and drop
4. Write correct formula
5. Balance the final equation
MgCl2 + CaS  MgS + CaCl2
Be(NO3)2 + K2SO4  2KNO3 + BeSO4
6
Specific Types of Double Replacement
Reactions
7
Precipitation – two aqueous solutions react
to form one solid precipitate and an
Beautiful Chemical Reactions
aqueous solution
Example:
KCl(aq) + AgNO3(aq)  KNO3 (aq) + AgCl (s)
8
Specific Types of Double Replacement Reactions
Acid/Base “Neutralization – An acid (always
starts with “H”) and a base (always ends in
“OH”) react to form a salt and water
Example:
HCl(aq) + NaOH(aq)  NaCl(aq) + H2O(l)
Acid – Base Neutralization Reactions
9
(write these reactions)
Acid + Base  Salt + Water
HCl + NaOH  NaCl + H2O
HNO3 + KOH
 KNO3
+ H2O
Double Replacement –
10
Precipitation Reactions
Soluble – able to be dissolved in water (aq)
Insoluble – not able to be dissolved in water (s)
Na+ and Cl- are called
SPECTATOR IONS.
They do not react and
remain dissolved in
solution
Solid
precipitate
Double Replacement – Precipitation Reactions
• Ionic compounds that dissolve in water split
apart into ions. Ions conduct electricity
when dissolved in solution. Electrolytes are
any ionic compounds which are soluble
and thus conduct electricity
• Ionic compounds that do not dissolve are
insoluble and are called precipitates.
These compounds form a solid when in
solution
11
Double Replacement – Precipitation Reactions
• Solubility was discovered by trial and error.
Over time, scientists developed a set of
rules (solubility rules) which help predict the
solubility of a substance
• When new compounds are formed in a
double replacement reaction, you must
identify the solubility (state) of the products
Soluble = (aq)
Insoluble = (s) - precipitate
12
Double Replacement –
Solubility Rules
SOLUBILITY RULES FOR COMMON IONIC COMPOUNDS IN WATER
Mainly water soluble
NO3C2H3O2ClO3ClBrISO42-
All nitrates are soluble
All acetates are soluble
All chlorates are soluble
All chlorides are soluble EXCEPT AgCl, Hg2Cl2, and PbCl2
All bromides are soluble EXCEPT AgBr, Hg2Br2, and HgBr2
All iodides are soluble EXCEPT AgI, Hg2I2, and HgI2
All sulfates are soluble EXCEPT CaSO4, SrSO4, BaSO4, PbSO4, Hg2SO4, and Ag2SO4
Mainly water insoluble
S2CO32CrO42PO43OH-
All sulfides are insoluble EXCEPT those of groups 1 & 2 and (NH4)2S
All carbonates are insoluble EXCEPT those of group 1 and (NH4)2CO3
All chromates are insoluble EXCEPT those of group 1 and (NH4)2CrO4
All phosphates are insoluble EXCEPT those of group 1 and (NH4)3PO4
All hydroxides are insoluble EXCEPT those of group 1, Ba(OH)2, Sr(OH)2, and Ca(OH)2
13
Double Replacement Reactions
14
Consider 2 Beakers: One with aqueous silver nitrate,
one with aqueous barium chloride
Draw a picture of each solution showing the ions present
Ag1+
NO31-
Ba 2+
Cl 1Cl 1-
15
Consider 2 Beakers: One with aqueous silver nitrate,
one with aqueous barium chloride
Draw a picture after the solutions are mixed (before new
compounds are formed
Ag1+
NO31Ba 2+
Cl 1-
Cl 1-
16
Consider 2 Beakers: One with aqueous silver nitrate,
one with aqueous barium chloride
Predict the products for any reaction that occurs and draw what
would be in the beaker (check solubility rules)
Write an equation for the reaction:
2AgNO3 (aq) + BaCl2 (aq) 
2AgNO3 (aq) + BaCl2 (aq)  2AgCl (s) + Ba(NO3) 2 (aq)
17
Consider 2 Beakers: One with aqueous silver nitrate,
one with aqueous barium chloride
Spectator Ions – Ions that remain as ions on both sides
of the equation (do not become part of a precipitate)
List the spectator ions in this example:
NO31Ba 2+
18
Double Replacement – Precipitation Reactions
19
Use the solubility rules to predict what will happen when the following
solutions are mixed. Label each new compound with an (aq) (electrolyte)
or (s) (precipitate). Circle the ions that would be spectator ions
2KNO3 + BaCl2
 Ba(NO3)2 (aq) + 2KCl
Na2SO4 + Pb(NO3)2
 2 NaNO3 (aq) + PbSO4 (s)
Na2S + Cu(NO3)2
 2 NaNO3 (aq) + CuS (s)
2NH4Cl + Pb(NO3)2
 2 NH4NO3 (aq) + PbCl2 (s)
1.
2.
3.
swap front ions
Criss-cross charges
balance equations
(aq)
Chapter 20.1
I can …….
20
• Identify oxidation – reduction reactions which
are also called Redox reactions
• Predict products for redox reactions
Oxidation Reduction Reactions
(Synthesis, Decomposition, Single Replacement,
Combustion)
21
In these reactions, electrons are transferred from one atom to
another
• Atoms that lose electrons (become more positive) are
oxidized
• Atoms that gain electrons (become more negative) are
reduced
• LEO says GER
or
OIL RIG
• Lose Electron Oxidized
Oxidation Is Loss
• Gain Electrons Reduced
Reduction Is Gain
How to determine if element gains or loses
electrons from its charge
e- carry negative charge! Remember this!
Element loses eElement “-” so element becomes more positive
0 - -1 = 0 +1
Element gains eElement “+” so element becomes more negative
0 + -1 = 0 - 1
22
Oxidation Reduction Reactions
Example 1: Identify the element that has been oxidized and23
the
element that has been reduced.
0
2Ca
+
0
O2 
2+
2-
2CaO
•
•
•
•
•
•
Ca became more positive
So Ca lost electrons
so it was oxidized
Oxygen became more negative
So O gained electron
so it was reduced
Step 1: Write the charge above any ions that are part of a compound
Step 2: Write a zero above any elements that exist by themselves (or as a
diatomic)
Step 3: Label atoms that have gained electrons (become more negative)
as reduced, and label atoms that have lost electrons (become more
positive) as oxidized
Oxidation Reduction Reactions
Example 2: Identify the element that has been oxidized and24
the
element that has been reduced.
0
Zn
•
•
•
•
•
•
1+ 1-
2+ 1-
0
+ 2HCl  ZnCl2 + H2
Zn became more positive
So Zn lost electrons
so Zn was oxidized
H became more negative
So H gained electrons
so H was reduced
Predicting Products of ReDox Reactions
• Synthesis – More than one reactant, but a
single product
• Example:
2Mg
+
O2  2MgO
• Decomposition – A single reactant, multiple
products
• Example:
• 2KNO3 
2 KNO2
+ O2
25
Predicting Products of ReDox Reactions
• Combustion – Reactants are always a
hydrocarbon and oxygen, products are
always CO2 (carbon dioxide) and H2O (water)
• Examples of hydrocarbons (must have C and H):
• CH4
• C2H6
• CH2O
• C6H12O6
Example:
CH4
+
2O2  CO2 + 2H2O
26
SINGLE REPLACEMENT:
One element replaces another
element in a compound
element + compound =
new element + new compound
A + BC 
B + AC
27
Predicting Products of ReDox Reactions
• Single Replacement – an element switches
partners: reaction does not always happen;
depends on the Activity Series (or reactivity
series)
• Example of a single replacement that does occur:
Na
+
MgCl2  NaCl + Mg
28
29
If a metal is higher on
the chart, it will
replace a metal that is
lower on the chart
Na is higher up
on chart than Mg
so Na is more
reactive
30
Example 1:
Ca
+
ZnI2 
CaI2
+
Zn
Example 1:
Ca
+
ZnI2 
Example 2:
Ca
+
NaI  NR – Ca is lower on chart
than Na
Write NR for No reaction when a reaction does not occur
For each of the following pairs of elements, circle the one
that will replace the other element in a compound 31
a. calcium, tin
b. bromine, fluorine
c. aluminum, potassium
d. iron, copper
e. iodine, chlorine
f. silver, lead
32
More Practice: Skeleton Equations – formulas only
Cu + AgNO3  CuNO3
Ca + HCl  CaCl2 + H2
Mg + CuCl2  MgCl2 + Cu
Fe + CuSO4 
FeSO4 + Cu
Zn + HCl  ZnCl2 + H
Cl2 + NaBr  NaCl + Br
33
END
DOUBLE REPLACEMENT:
AB + CD  CB + AD
compound + compound =
new compound + new compound
Cations and Anions switch places
But there must be a reason why they
switch places ……………
34
35
B
A+
C+
D
A gas forms and leaves
A precipitate forms and settles out
Water is formed
36
Solubility Rules:
1. Na+ K+
NH4+ salts are soluble
2. NO31- salts are soluble
3. Cl1- salts are soluble
EXCEPT: AgCl PbCl2 and HgCl
4. SO42- salts are soluble
EXCEPT: BaSO4 PbSO4 and CaSO4
37
Four general types of chemical reactions
+
+
..
+
38
Four general types of chemical reactions
+
+
..
+
39
40
Synthesis
41
Decomposition
42
Synthesi
s
Decomposition
Single Replacement
43
Synthesi
s
Decomposition
Single Replacement
Double Replacement
COMBUSTION: (Burning)
Reacts with oxygen
•• Produces oxides of the fuel
•• Hydrocarbon or any C,H,O compound
•• Produces CO2 and H2O
•• Produces energy (heat and light)
•• Exothermic reaction
•• Example: CH4 + 2O2  CO2 + 2 H2O
••
44
OXIDATION:
•• Metal or nonmetal reacts with oxygen
•• Produces an oxide of the element
•• Exothermic reaction produces heat
Examples:
C + O2  CO2
2Ca + O2 2CaO
Na + O2 Na2O
45
•
•
•
•
•
•
•
•
•
•
Synthesis A + B  AB
Decomposition AB A + B
Single Replacement
A + BC  B + AC
Double Replacement
AB + CD AD + CB
Acid – Base (Neutralization)
Acid + Base  Salt + Water
Combustion
Oxidation
46
Predicting Products of ReDox Reactions
• Synthesis – More than one reactant, but a
single product
• Example:
0
2Mg
+
0
+2 -2
O2  2MgO
• Decomposition – A single reactant, multiple
products
• Example:
+1 +5 -2
• 2KNO3 
+1+3 -2
2 KNO2
0
+ O2
47