Types of Chemical Reactions
There are 5 main types of chemical reactions:
Combustion: The resulting products
are always Oxygen, (CO2) and Water, (H2O)
Single Displacement: A + BC-----> AC + B
Double Displacement: AB + CD
-----> AD + BC
Synthesis: A + B -----> AB
Decomposition: AB-----> A + B
Combustion is quite simple. As long as there is Oxygen, Hydrogen and Carbon in the reactants, it creates Water and Hydrogen
gas as the products.
Synthesis is basically taking the reactants, combining them, and creating a product. So, for example, we can take Magnesium
and Oxygen. It is written as:
Mg + O2 ---> MgO
The oxidation states of Magnesium and Oxygen are both 2. We know this because Magnesium wants to lose 2 electrons to
get a stable octet, and Oxygen wants to gain 2 electrons to become a stable octet. The overall charge of this bond is neutral.
Since we can divide by a common factor of 2, it will be written as MgO.
Single displacement written like this:
Li + MgO ---> Li2O + Mg
Basically, the lonely Lithium "kicks" out the Magnesium and bonds with Oxygen. In order for Lithium to kick out the Magnesium,
it must be higher on the activity series than Magnesium, which it is. Lithium's oxidation state is 1, since it wants to lose
1 electron. Oxygen's oxidation state is 2 because it wants to gain 2 electrons. So, when you criss cross down, you get Li2O.