Lecciòn 1Recognizing Four Types of Chemical Reactions

St. Anne` School

Today we shall look at four types of chemical reactions ……

1.Synthesis2.Decomposition3.Single replacement4.Double replacement

A chemical reaction takes place when two or more substances combine and yield one or more other substances with different characteristics.

Today we shall look at four types of chemical reactions ……

1.Synthesis2.Decomposition3.Single replacement4.Double replacement

Today we shall look at four types of chemical reactions ……

1.Synthesis2.Decomposition3.Single replacement4.Double replacement

Synthesis occurs when two substances combine

chemically to yield a new substance with different properties.

For example

Sodium plus Chlorine yield Salt Na + Cl NaCl

Decomposition takes place when a substance is

broken down into two or more substances with

different properties.

For example

2H2O O2 + 4HWater yields Oxygen and Hydrogen

Single replacement takes place when a substance takes the place of another substance in a compound.

For example

2Al + 3Ag2 S 3Ag + Al2S3

Aluminum plus Silver sulfide yields Silver plus Aluminum sulfide

Double Replacement takes place when substances exchange places.

For example

NaOH + H2SO4 Na2SO4 + H2O

Sodium hydroxide and Sulfuric acid yield Sodium sulfate and water

See if you can tell what the following type of Reaction is

4Fe + 3O2 2Fe2O3