8th Grade Integrated Science Chapter 9 Lesson 2 on Types of Chemical Reactions. This chapter explains five different types of reactions: synthesis, decomposition, single replacement, double replacement, and combustion.

1. Types of Chemical Reactions
Chapter 9.2
p 311-315

2. There are many different types
of reactions. Most fit into 4
major categories.
•
•
•
•
Synthesis
Decomposition
Replacement
Combustion

3. Synthesis Reactions
• A synthesis is a type of chemical reaction
in which two or more substances combine
and form one compound.
– Example:
• 2Na + Cl^2 => 2NaCl
• 2H^2 + O^2 => 2H^2O
• H^2O + SO^3 => H^2SO^4

5. Decomposition Reactions
• In a decomposition reaction, one compound
breaks down and forms two or more substances.
– So one reactant will form two or more products.
– The reverse of synthesis.
– Example:
• CaCO^3 => CaO + CO^2
• 2H^2O => 2H^2 + O^2
• 2KClO^3 => 2KCl + 3O^2

7. Replacement Reactions
• Single-replacement
– In a single-replacement reaction, one element replaces another
element in a compound.
– In this reaction one element and a compound react and form a
different element and a different compound.
– Example:
• Fe + CuSO^4 => FeSO^4 + Cu
• Zn + 2HCl => ZnCl^2 + H^2

9. Replacement Reactions
• Double-Replacement
– In a double-replacement reaction, the negative ions in two
compounds switch places, forming two new compounds.
– In this reaction you start with 2 compounds and end with two
different compounds.
– Example:
• NaCl + AgNO^3 => NaNO^3 + AgCl
• HCl + FeS => FeCl^2 + H^2S

11. Combustion Reactions
• Combustion is a chemical reaction in
which a substance combines with oxygen
and releases energy.
– This energy usually is released as thermal
energy and light energy.
– Burning is a common combustion reaction.