chapter 9.2: types of chemical reactions
DESCRIPTION
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.TRANSCRIPT
Types of Chemical Reactions
Chapter 9.2p 311-315
There are many different types of reactions. Most fit into 4
major categories.
• Synthesis
• Decomposition
• Replacement
• Combustion
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
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
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
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
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.