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.
Types of Chemical Reactions
There are many different types
of reactions. Most fit into 4
• A synthesis is a type of chemical reaction
in which two or more substances combine
and form one compound.
• 2Na + Cl^2 => 2NaCl
• 2H^2 + O^2 => 2H^2O
• H^2O + SO^3 => H^2SO^4
• 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.
• CaCO^3 => CaO + CO^2
• 2H^2O => 2H^2 + O^2
• 2KClO^3 => 2KCl + 3O^2
– 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.
• Fe + CuSO^4 => FeSO^4 + Cu
• Zn + 2HCl => ZnCl^2 + H^2
– 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
• NaCl + AgNO^3 => NaNO^3 + AgCl
• HCl + FeS => FeCl^2 + H^2S
• 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.