Topic: Reaction Stoichiometry


Reaction Stoichiometry (which is sometimes shortened to just Stoichiometry, even though there are other types of Stoichiometry) is a technique in Chemistry used to calculate the relative proportions in which Chemical Elements form chemical compounds or in which chemical stabstances react in chemical reacations.


Here's an example reaction stoichiometry calculation.

  2H2 + O2 → 2H2O

(Note, you need to understand the notation for the Chemical Elements to understand this example.)

Symbols in Example

In the above equation H2 is how we typically find Hydrogen, such as hydrogen gas. (Hydrogen atoms often bind together in pairs.)

Also in the above equation O2 is how we typically find Oxygen, such as the oxygen we breath. (Oxygen atoms often bind together in pairs.)

And H2O is Water.

Understanding the Example

So, this equation says you need to two molecules of Hydrogen (H2) for every one molecule of Oxygen (O2) and that will create 2 molecules of Water (H2O).

But it is the ratios that matter here. So, this also says that with 4 H2 reacted with 2 O2 gives us 4 H2O molecules.

And says that 6 H2 reacted with 3 O2 gives us 6 H2O molecules.

And also says that 8 H2 reacted with 4 O2 gives us 8 H2O molecules.


The reason equations like that are important is because we can use this information to figure out exactly how many Grams or Litres of a substance to react together, and how much of the resul we are going to get. And that is important!

See Also
-- Mirza Charles Iliya Krempeaux