Stoichiometry (Quantitative Chemistry)

Stoiciometry is a branch of Chemistry that deals with the quantitative anaysis 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 we use in stoichiometry, they are...

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

SYNTHESIS

A synthesis reaction is when two or more simple compounds combine to form a more complicated one. The general form for this reaction is:

A + B ---> AB

DECOMPOSITON

A decomposition reaction is the opposite of a synthesis reaction - a complex molecule breaks down to make simpler ones. These general form for this reaction is:
AB ---> A + B

Example: 2 H2O ---> 2 H2 + O

 
SINGLE REPLACEMENT

This is when one element trades places with another element in a compound. The general form for this reaction is:

A + BC ---> AC + B (A is a metal)
OR
A +BC---> C+ BA (A is a non-metal)
Example: Mg + 2 H2O ---> Mg(OH)2 + H2


DOUBLE REPLACEMENT

This is when the anions and cations of two different molecules switch places, forming two entirely different compounds. These general form for this reaction is:
AB + CD ---> AD + CB
Example: Pb(NO3)2 + 2 KI ---> PbI2 + 2 KNO3

NEUTRALIZATION

Also known as Acid-base neutralization: This is a kind of double displacement reaction that takes place when an acid and base react. The H+ ion in the acid reacts with the OH- ion in the base, causing water to form. The product of this reaction is some ionic salt and water:
HA + BOH ---> H2O + BA

Example: HBr + NaOH ---> NaBr + H2O

COMBUSTION

Combustion reactions happen when oxygen combines with another compound to form water and carbon dioxide. These reactions are exothermic.

Example:  C10H8 + 12 O2 ---> 10 CO2 + 4 H2O

TEST YOUR KNOWLEDGE ON REACTIONS! (: