1. Synthesis, Decomposition &Combustion
Unit 6 – Lesson 2
Synthesis, Decomposition &Combustion

2. A + B  AB 1. Synthesis 2 or more reactants form one product Examples
Types of chemical reactions
1. Synthesis
2 or more reactants form one product
A + B  AB
Examples
2 H2 + O2  2 H2O
CaO + H2O  Ca(OH)2

3. Balance the equation: 2Mg + O2 → 2MgO
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

4. Binary because one compound is split into two elements
2. Decomposition
1 reactant forms two or more products
Binary because one compound is split into two elements
AB  A + B
Examples
2 HgO  2 Hg + O2
2 NaCl  2 Na + Cl2
2 Ag₂O  4 Ag + O2
video

5. Complete the skeleton equations :
Use page 6 of your reference packet to identify and predict products of other types of decomposition reactions
M means any metal
CuCO3 
Complete the skeleton equations :
Ca(OH)2 
KClO3 
H2SO4 
Ca(HCO3)2 
Videos are linked on each picture above
CuO + CO2
KCl + O2
CaCO3 + CO2 + H2O
SO3 + H2O
CaO + H2O

6. Copper(II) oxide  Copper + Oxygen
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

7. What products will be formed when Al2(CO3)3 decomposes
What products will be formed when Al2(CO3)3 decomposes? Balance the equation.
Al2(CO3)3  3
CO2 +
Al2O3 Al C O 3 9

8. 3. Combustion
When a compound (usually a hydrocarbon) reacts with oxygen producing water, carbon dioxide and heat.
hydrocarbon  compound made of H & C
Examples
No hydrocarbon:
C2H5OH + 3 O2  2 CO2 + 3 H2O
Hydrocarbon:
CH4 + 2 O2  CO2 + 2 H2O

9. Predict the products of the following reaction: C6H14 + O2 →
hydrocarbon
oxygen
Combustion
When balancing combustion equations, focus on the hydrocarbon first and match the carbons……
If the equation will not balance with 1 hydrocarbon, make it 2, and so forth. 2
C6H O2 → CO H2O 19 12 6 14 7 12 C H O 6 12 28 14 28 38 13 19 38