1. Synthesis, Combustion, and Decomposition Reactions
Unit 5 Lesson 2
Synthesis, Combustion, and Decomposition Reactions
Demos
It is Eggothermic

2. Types of Reactions Synthesis Reaction Decomposition Reaction
Video Link
Synthesis Reaction
Decomposition Reaction
Single-Replacement Reaction
Double-Replacement Reaction
Combustion Reaction
More is listed about each type on page 6 of your reference packet

3. A + B  AB Synthesis Reaction Examples 2 H2 + O2  2 H2O
2 or more reactants form one product.
A + B  AB
Examples
2 H2 + O2  2 H2O
CaO + H2O  Ca(OH)2

4. Combustion Reaction
An element or compound (generally a hydrocarbon) reacts with oxygen producing carbon dioxide, water, and heat.
This is a special type of synthesis
Example C2H5OH + 3 O2  2 CO2 + 3 H2O

5. Decomposition Reaction
One reactant forms 2 or more products.
AB  A + B
Examples
2 HgO  2 Hg + O2
2 NaCl  2 Na + Cl2

6. Decomposition
Binary: split apart into two elements.
Ag₂O  Ag + O2
If not binary, refer to reference packet page 6
“M” means any metal
Example – Metal Carbonate
Na2CO3  Na2O + CO2
Example – Metal hydroxide
Ca(OH)2  CaO + H2O

7. Copper(II) oxide  Copper + Oxygen
Sample Problem 1
Copper(II) Oxide will decompose when heated strongly.
Give the word and formula equation.
Balance the equation
Copper(II) oxide  Copper + Oxygen
CuO  Cu + O2
2CuO  2Cu + O2

8. Sample 2
Predict the products of a synthesis reaction between Magnesium and Oxygen.
Mg + O2 → MgO
Balance the equation:
2Mg + O2 → 2MgO
Oxygen is a diatomic!
Mg2+ O2-
You should not balance the equation and predict products at the same time, they are separate processes

9. Sample 3 What products will be formed when Al2(CO3)3 decomposes?
Balance the equation AFTER predicting the products
Al2(CO3)3 →???? Look at reference packet
Al2(CO3)3 → Al2O3 + CO2
___Al2(CO3)3 → ___Al2O3 + ___CO2
Al2(CO3)3 → Al2O3 + 3CO2

10. Sample 4
Predict the products of the following reaction: C6H14 +O2 → ?????
C6H14 is a hydrocarbon reacting with O2, making this a combustion reaction. The products are water and carbon dioxide.
C6H14 +O2 → H2O + CO2
__C6H14 +__O2 → __H2O + __CO2
2C6H14 +19O2 → 14H2O + 12CO2