1. Recognizing Types of Chemical Reactions
How can one identify the type of chemical reaction from an equation?

2. Synthesis (Combination)
Two or more reactants combine to form one product
A + B  AB
Examples:
2 H2 + O2  2 H2O
4 Fe + 3 O2  2 Fe2O3
CO2 + H2O  H2CO3

3. Decomposition One reactant breaks apart into two or more products
AB  A + B
Examples:
2 HI  H2 + I2
CaCO3  CaO + CO2

4. Single Replacement Two reactants and two products (look for elements)
element + compound  element + compound
A + BC  B + AC
Examples:
Cu + 2 AgNO3  Cu(NO3)2 + 2 Ag
Cl2 + 2 NaBr  2 NaCl + Br2

5. Double Replacement Two reactants and two products (all are compounds)
Two compounds switch positive and negative ions
AB + CD  AD + CB
Examples:
AgNO3 + NaCl  AgCl + NaNO3
Na2S + 2 HCl  H2S + 2 NaCl

6. Organic Combustion Two reactants and two products
(C,H + O2  CO2 + H2O)
Examples:
CH4 + 2 O2  CO2 + 2 H2O
2 C2H6 + 7 O2  4 CO2 + 6 H2O