Unit 4 (Ch. 8) Chemical
Reactions
8.2 Types of Reactions
DECOMPOSITION REACTIONS
A. Define decomposition reaction:
A single compound is broken down into two
or more products.
Predicting Decomposition
Reactions (Notepack, pg. 4)
8.2 Types of Reactions
DECOMPOSITION REACTIONS
B. Write a general formula for a
decomposition reaction:
Most compounds are broken down when
energy is added (often in the form of heat
or electricity)
8.2 Types of Reactions
DECOMPOSITION REACTIONS
There are 5 Helpful Hints for Decomposition
Reactions (Notepack pg. 5)
AB A + B
8.2 Types of Reactions
DECOMPOSITION REACTIONS
1. Some oxy-acids, when heated,
decompose to form water and the
nonmetal oxide.
Oxy-acids are acids with oxygen in them:
H3PO4
HNO3
(NOT: HCl, HBr, etc)
8.2 Types of Reactions
DECOMPOSITION REACTIONS
1. Some oxy-acids, when heated,
decompose to form water and the
nonmetal oxide.
A nonmetal oxide is just that, a nonmetal
bonded with oxygen.
Examples: P2O3, N2O5, SO3, etc
1
8.2 Types of Reactions
DECOMPOSITION REACTIONS
1. Some oxy-acids, when heated,
decompose to form water and the
nonmetal oxide.
Using your polyatomic ion chart, determine the formula for the acid.
Example: Sulfuric acid is heated
8.2 Types of Reactions
DECOMPOSITION REACTIONS
1. Some oxy-acids, when heated,
decompose to form water and the
nonmetal oxide.
Example: Sulfuric acid is heated
H2SO4 Oxy-acid
8.2 Types of Reactions
DECOMPOSITION REACTIONS
1. Some oxy-acids, when heated,
decompose to form water and the
nonmetal oxide.
Example: Sulfuric acid is heated
H2SO4 H2O + ____
+
water
+
nonmetal oxide
8.2 Types of Reactions
DECOMPOSITION REACTIONS
1. Some oxy-acids, when heated,
decompose to form water and the
nonmetal oxide.
Example: Sulfuric acid is heated
H2SO4 H2O + SO3
Oxy-acid
water
+
nonmetal oxide
After transferring the H2O over, from the left to the right, what is left?
8.2 Types of Reactions
DECOMPOSITION REACTIONS
1. Some oxy-acids, when heated,
decompose to form water and the
nonmetal oxide.
Example: Nitric acid is heated
8.2 Types of Reactions
DECOMPOSITION REACTIONS
1. Some oxy-acids, when heated,
decompose to form water and the
nonmetal oxide.
Example: Nitric acid is heated
HNO3 Oxy-acid
water
+
nonmetal oxide
2
8.2 Types of Reactions
DECOMPOSITION REACTIONS
8.2 Types of Reactions
DECOMPOSITION REACTIONS
1. Some oxy-acids, when heated,
decompose to form water and the
nonmetal oxide.
Example: Nitric acid is heated
1. Some oxy-acids, when heated,
decompose to form water and the
nonmetal oxide.
Example: Nitric acid is heated
HNO3 H2O + _____
2HNO3 H2O + _____
Oxy-acid
Oxy-acid
water
+
nonmetal oxide
After transferring the H2O over, what is left?
8.2 Types of Reactions
DECOMPOSITION REACTIONS
1. Some oxy-acids, when heated,
decompose to form water and the
nonmetal oxide.
Example: Nitric acid is heated
water
+
nonmetal oxide
After transferring the H2O over, what is left?
8.2 Types of Reactions
DECOMPOSITION REACTIONS
2. Some metallic hydroxides (bases), when
heated, decompose to form the metal oxide
and water.
2HNO3 H2O + N2O5
Oxy-acid
water
+
nonmetal oxide
8.2 Types of Reactions
DECOMPOSITION REACTIONS
2. Some metallic hydroxides (bases), when
heated, decompose to form the metal oxide
and water.
Metallic hydroxides include:
Ca(OH)2 calcium hydroxide
Mg(OH)2 magnesium hydroxide
NaOH sodium hydroxide
8.2 Types of Reactions
DECOMPOSITION REACTIONS
2. Some metallic hydroxides (bases), when
heated, decompose to form the metal oxide
and water.
Example: Sodium hydroxide is heated.
NaOH 3
8.2 Types of Reactions
DECOMPOSITION REACTIONS
2. Some metallic hydroxides (bases), when
heated, decompose to form the metal oxide
and water.
Example: Sodium hydroxide is heated.
NaOH H2O + ______
8.2 Types of Reactions
DECOMPOSITION REACTIONS
2. Some metallic hydroxides (bases), when
heated, decompose to form the metal oxide
and water.
Example: Sodium hydroxide is heated.
NaOH H2O + Na2O
…but it’s not balanced.
8.2 Types of Reactions
DECOMPOSITION REACTIONS
2. Some metallic hydroxides (bases), when
heated, decompose to form the metal oxide
and water.
Example: Sodium hydroxide is heated.
2NaOH H2O + Na2O
Sodium hydroxide
“yields”
water
and
sodium oxide
8.2 Types of Reactions
DECOMPOSITION REACTIONS
2. Some metallic hydroxides (bases), when
heated, decompose to form the metal oxide
and water.
Example: Calcium hydroxide is heated.
Ca(OH)2 8.2 Types of Reactions
DECOMPOSITION REACTIONS
8.2 Types of Reactions
DECOMPOSITION REACTIONS
2. Some metallic hydroxides (bases), when
heated, decompose to form the metal
oxide and water.
Example: Calcium hydroxide is heated.
2. Some metallic hydroxides (bases), when
heated, decompose to form the metal
oxide and water.
Example: Calcium hydroxide is heated.
Ca(OH)2 H2O + _____
Ca(OH)2 H2O + CaO
Calcium hydroxide
“yields”
water
and
calcium oxide
4
8.2 Types of Reactions
DECOMPOSITION REACTIONS
3. Some metallic CARBONATES, when
heated, decompose to form the metal
oxide and carbon dioxide gas.
Metallic carbonate
metal oxide
8.2 Types of Reactions
DECOMPOSITION REACTIONS
3. Some metallic CARBONATES, when heated,
decompose to form the metal oxide and
carbon dioxide gas.
Examples of metallic carbonates:
Copper (II) carbonate CuCO3
and carbon dioxide
8.2 Types of Reactions
DECOMPOSITION REACTIONS
8.2 Types of Reactions
DECOMPOSITION REACTIONS
3. Some metallic CARBONATES, when heated,
decompose to form the metal oxide and
carbon dioxide gas.
Examples of metallic carbonates:
Copper (II) carbonate CuCO3
3. Some metallic CARBONATES, when heated,
decompose to form the metal oxide and
carbon dioxide gas.
Examples of metallic carbonates:
Copper (II) carbonate CuCO3
CuCO3
CuCO3
Metallic carbonate
Metallic carbonate
metal oxide
and carbon dioxide
8.2 Types of Reactions
DECOMPOSITION REACTIONS
3. Some metallic CARBONATES, when heated,
decompose to form the metal oxide and
carbon dioxide gas.
Examples of metallic carbonates:
Copper (II) carbonate CuCO3
CuCO3
Metallic carbonate
CuO
metal oxide
+
CO2
and carbon dioxide
____
metal oxide
+
CO2
and carbon dioxide
8.2 Types of Reactions
DECOMPOSITION REACTIONS
3. Some metallic CARBONATES, when heated,
decompose to form the metal oxide and
carbon dioxide gas.
Examples of metallic carbonates:
Copper (II) carbonate CuCO3
CuCO3
+
CO2
Copper (II) carbonate
“yields”
copper (II) oxide
and
carbon dioxide
Metallic carbonate
metal oxide
and carbon dioxide
CuO
5
8.2 Types of Reactions
DECOMPOSITION REACTIONS
8.2 Types of Reactions
DECOMPOSITION REACTIONS
4. Some metallic CHLORATES, when
heated, decompose to form the metal
chloride and oxygen gas.
Examples of metallic chlorates:
Potassium chlorate KClO3
Aluminum chlorate Al(ClO3)3
Magnesium chlorate Mg(ClO3)2
4. Some metallic CHLORATES, when
heated, decompose to form the
metal chloride and oxygen gas.
Change this
in your
notes!!!
8.2 Types of Reactions
DECOMPOSITION REACTIONS
4. Some metallic CHLORATES, when heated,
decompose to form the metal chloride and
oxygen gas.
Examples:
Potassium chlorate is heated
8.2 Types of Reactions
DECOMBINATION REACTIONS
4. Some metallic CHLORATES, when heated,
decompose to form the metal chloride and
oxygen gas.
Examples:
Potassium chlorate is heated
KClO3
8.2 Types of Reactions
DECOMBINATION REACTIONS
4. Some metallic CHLORATES, when heated,
decompose to form the metal chloride and
oxygen gas.
Examples:
Potassium chlorate is heated
KClO3
Metallic chlorate
_____
metal chloride
+
8.2 Types of Reactions
DECOMBINATION REACTIONS
4. Some metallic CHLORATES, when heated,
decompose to form the metal chloride and
oxygen gas.
Examples:
Potassium chlorate is heated
O2
and oxygen gas
KClO3
Potassium chlorate
“yields”
Metallic chlorate
KCl
potassium chloride
metal chloride
+
O2
and
oxygen gas
and oxygen gas
6
8.2 Types of Reactions
DECOMBINATION REACTIONS
8.2 Types of Reactions
DECOMBINATION REACTIONS
4. Some metallic CHLORATES, when heated,
decompose to form the metal chloride and
oxygen gas.
Examples:
Potassium chlorate is heated
5. Some binary compounds, when heated or
treated with electricity, will decompose into
their elements.
2KClO3
Binary compounds are made of just 2 different elements
Potassium chlorate
“yields”
Metallic chlorate
2KCl
potassium chloride
metal chloride
Now, it is balanced!!
+ 3O2
and
oxygen gas
and oxygen gas
8.2 Types of Reactions
DECOMBINATION REACTIONS
5. Some binary compounds, when heated or
treated with electricity, will decompose into
their elements.
Examples of binary compounds:
Water
H2O (same as H OH)
Silver oxide
Ag2O
Iron (II) oxide
FeO
Mercury (II) oxide
HgO
8.2 Types of Reactions
DECOMBINATION REACTIONS
8.2 Types of Reactions
DECOMBINATION REACTIONS
5. Some binary compounds, when heated or
treated with electricity, will decompose into
their elements.
Examples:
Water decomposes when electricity is applied
8.2 Types of Reactions
DECOMBINATION REACTIONS
5. Some binary compounds, when heated or
treated with electricity, will decompose into
their elements.
Examples:
Water decomposes when electricity is applied
5. Some binary compounds, when heated or
treated with electricity, will decompose into
their elements.
Examples:
Water decomposes when electricity is applied
H2O H2O H2
Water
Water
+ O2
Hydrogen gas + Oxygen gas
…but it’s not balanced.
7
8.2 Types of Reactions
DECOMBINATION REACTIONS
5. Some binary compounds, when heated or
treated with electricity, will decompose into
their elements.
Examples:
Water decomposes when electricity is applied
2H2O 2H2
Water
+
8.2 Types of Reactions
DECOMBINATION REACTIONS
5. Some binary compounds, when heated or
treated with electricity, will decompose into
their elements.
Examples:
Silver oxide decomposes when heated
O2
Hydrogen gas + Oxygen gas
8.2 Types of Reactions
DECOMBINATION REACTIONS
8.2 Types of Reactions
DECOMPOSITION REACTIONS
5. Some binary compounds, when heated
or treated with electricity, will decompose
into their elements.
Examples:
Silver oxide decomposes when heated
5. Some binary compounds, when heated
or treated with electricity, will decompose
into their elements.
Examples:
Silver oxide decomposes when heated
Ag2O
Silver oxide
Ag2O
Silver oxide
8.2 Types of Reactions
DECOMPOSITION REACTIONS
5. Some binary compounds, when heated
or treated with electricity, will decompose
into their elements.
Examples:
Silver oxide decomposes when heated
2Ag2O
Silver oxide
Ag + O2
Silver + Oxygen gas
8.2 Types of Reactions
DECOMPOSITION REACTIONS
Practice Examples:
With the person next to you, predict the product in
the following decomposition reactions.
(Use the
from above!)
4Ag + O2
Silver + Oxygen gas
8
8.2 Types of Reactions
DECOMPOSITION REACTIONS
8.2 Types of Reactions
DECOMPOSITION REACTIONS
Practice Examples: Write the balanced equations
for the following decompositions…
Practice Examples: Write the balanced equations
for the following decompositions…
(Use the
from above!)
1. Calcium carbonate solid is heated
(Use the
from above!)
1. Calcium carbonate solid is heated
CaCO3 CaO + CO2
8.2 Types of Reactions
DECOMPOSITION REACTIONS
8.2 Types of Reactions
DECOMPOSITION REACTIONS
Practice Examples: Write the balanced equations
for the following decompositions…
Practice Examples: Write the balanced equations
for the following decompositions…
(Use the
from above!)
2. Magnesium chlorate solid is heated
(Use the
from above!)
2. Magnesium chlorate solid is heated
Mg(ClO3)2 MgCl2 + 3O2
8.2 Types of Reactions
DECOMPOSITION REACTIONS
8.2 Types of Reactions
DECOMPOSITION REACTIONS
Practice Examples: Write the balanced equations
for the following decompositions…
Practice Examples: Write the balanced equations
for the following decompositions…
(Use the
from above!)
3. Hydroiodic acid is heated
(Use the
from above!)
3. Hydroiodic acid is heated
2HI I2 + H2
9
8.2 Types of Reactions
DECOMPOSITION REACTIONS
8.2 Types of Reactions
DECOMPOSITION REACTIONS
Practice Examples: Write the balanced equations
for the following decompositions…
Practice Examples: Write the balanced equations
for the following decompositions…
(Use the
from above!)
4. Magnesium hydroxide is heated
(Use the
from above!)
4. Magnesium hydroxide is heated
Mg(OH)2 H2O + MgO
8.2 Types of Reactions
DECOMPOSITION REACTIONS
8.2 Types of Reactions
DECOMPOSITION REACTIONS
Practice Examples: Write the balanced equations
for the following decompositions…
Practice Examples: Write the balanced equations
for the following decompositions…
(Use the
from above!)
5. Sulfurous acid is heated
(Use the
from above!)
5. Sulfurous acid is heated
H2SO3 H2O + SO2
For the TEST on Friday…
This concludes any new material we will be
covering before Christmas Break. You are
strongly encouraged to prepare for the test
which has the following Objectives on it:
Balancing Equations
Predicting Combination Reactions
Predicting Decomposition Reactions
Distributive Practice: Review from past
Tests
10