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.