What are 3 conversion factors used in stoichiometry?

1 Answer
May 14, 2017

Molar Mass (moles #rightleftharpoons# grams)
Stoichiometric Coefficients (moles #-># moles)
Avagadro's number (moles #rightleftharpoons# atoms/molecules.


There are a number of calculations you'll need to do in stoichiometry, but the aforementioned three are the most common.

Your molar mass is what you'll need to use to go from grams of your species to moles of your species (and vice-versa). Every element's molar mass is listed on the periodic table, and the molar mass of a compound can be found by simply adding the molar masses of all its constituent elements.

The stoichiometric coefficients tell you the molar ratio between two species in a balanced chemical equation. For example, consider the generic reaction below:

#A + 2B -> AB_2#

What this tells you is that every 1 mol of #A# reacts with 2 mols of #B# to produce 1 mol of #AB_2#. Given a molar quantity of any one species, this allows you to determine how many moles of the others you can produce/will react.

Avogadro's number provides a relationship between moles and the number of atoms/molecules. It tells you that, by definition, you have #6.022 * 10^23# atoms/molecules of species per every mole of species. This allows you to move back and forth between those two quantities.

This diagram sums it up nicely:


Hope that helps :)