Stoichiometry - Quantitative Chemistry

Stoichiometry is a branch of chemistry that deals with the quantitative analysis of chemical reactions. It is a generalization of mole conversions to chemical reactions. Understanding the 6 types of chemical reactions is the foundation of stoichiometry.
There are 6 types of reactions:

1. Synthesis (formation)
2. Decomposition
3. Single Replacement
4. Double Replacement
5. Neutralization
6. Combustion

1. Synthesis
Synthesis is the combination of 2 elements (a cation and an anion) together to make a single element
Examples:

1. 2H2 + O2 = 2H2O
2. 4K + O2 = 2K2O

2. Decomposition 
Decomposition is generally the opposite of Synthesis. Remember, always assume the compounds decompose into elements during decomposition
Examples:

1. 4H3PO4 -> 6H2 + P4 + 8O2
2. 2C12H22O11 -> 24C + 22H2 + 11O2

3. Single Replacement (A + BC -> B + AC)
Example:

1. Ca + 2KCl -> 2K + CaCl2   

4. Double Replacement (AB + CD -> AD + BC)
Examples:

1. MgCl2 + K2SO4 -> MgSO4 + 2KCl
2. AgNO3 + NaCl -> AgCl + NaNO3

5. Neutralization
Neutralization is a reaction between an acid and a base
Example: 

1. H2SO4 + 2KOH -> 2HOH + K2SO4

6. Combustion
Combustion is a reaction with something (usually hydrocarbon) with air. Hydrocarbon combustion always produces CO2 and H2O
Example:

1. CH4 + 2O2 -> CO2 + 2H2O