1. Single Replacement Reactions: A +BC  AC + B
An element takes the place of another element in a compound. It could be a metal taking the place of another metal or hydrogen or a halogen taking the place of another halogen.
Mg(s) + FeSO4(aq) 
Cl2(g) + KBr(aq) 
Fe(s) + MgSO4 (aq) 
Br2 (aq) + KCl(aq) 
MgSO4 (aq) + Fe(s)
Magnesium is more active than Iron and
KCl(aq) + Br2 (aq)
Chlorine is more active than Bromine!
N.R.
N.R.

2. Activity Series: Activity Decreases F Activity Cl Decreases Br I
For metals:
Lithium Li Cs Rb K Ba Sr Ca Na La Mg Be Al Mn Zn Cr Fe Cd Co Ni Sn Pb H
Cesium
Rubidium
Activity Series:
Potassium
Barium
Strontium
For halogens:
Activity
Decreases
Calcium
Sodium
Activity
Decreases F Cl Br I
Fluorine
Lanthanum
Magnesium
Chlorine
Beryllium
Bromine
Aluminum
Iodine
Manganese
Zinc H Cu Hg Ag Pt Au
Hydrogen
Chromium
Iron
Copper
Cadmium
Mercury
Cobalt
Silver
Nickel
Tin
Platinum
Lead
Gold
Hydrogen

3. Double Replacement Reactions :
AB +CD  AD + CB
It is a reaction between two ionic compounds in
which the ions switch positions:
The positive of the first combines with the
negative of the second and the positive of
the second with the negative of the first.
MgCO3(s) + FeSO4(aq) 
BaCl2(aq) + KBr(aq) 
Fe(NO3)3(aq)+Ca3(PO4)2(s)
CuBr2 (aq) + KCl(aq) 
MgSO4 (aq) + FeCO3 (s) 2
BaBr2(aq) + KCl(aq) 2 2
Ca(NO3)2(aq)+ FePO3(s) 3 2 2
CuCl2 (aq) + KBr(aq) 2

4. Double-replacement reactions
One of the types of double-replacement reactions is when a
precipitate is formed. When a precipitate is formed, the
compound will be either insoluble or slightly soluble. An
example of this type of reaction is:
Pb(NO3)2(aq) + 2KI (aq) -->
PbI2(s) + 2KNO3 (aq)
When one of the products is a gas, double-replacement
reactions also occur. For example:
FeS(s) + 2HCl(aq) -->
H2S(g) + FeCl2(aq)
An example of a double-replacement reaction where water
is one of the products is:
HCl(aq)+ NaOH(aq) -->
NaCl (aq) + H2O(l)
This is a neutralization reaction:
Acid + Base = Salt + Water

5. Combustion of a hydrocarbon: Hydrocarbon+O2(g)C O2(g)+H2O(g)
When a substance combines with oxygen releasing a large amount of energy in the form of light and heat, it is a combustion reaction. An example of a combustion reaction is:
C3H8 + 5O2 -->
3CO2 + 4H2O +  +

6. Decomposition Reactions: ABC…  A +B +C …
Decomposition: the breaking down of a compound into one or more substances. (usually energy is required)
EXAMPLES: CO2 (g) ----- C(s) + O2(g) Fe2O3 (s)- 4Fe(s) + 3O2 (g)
Generalizations:
A binary compound decomposes into two elements.
A hydroxide of the metal decomposes into an oxide of the metal and water.
A ternary salt decomposes into an oxide of the metal and an oxide of the non metal.
A ternary or oxoacid decomposes into the oxide of a non metal and water .