The mole is the most fundamental measurement quantity in chemistry.
When you are trying to solve problems and don't know what to do,
try to convert whatever you have into moles, it is almost always the
best place to start. I call moles the "super
secret unit of chemistry" because you need to understand and be
able to use the concept of moles to do chemistry calculations. It
is fundamental to further study in chemistry. It is the first
"secret" of being able to
The mole is how we count in chemistry. One mole is equal to
particles. It is no different in concept than a dozen which most
know is 12 or a ream (usually in reference to paper) being equal to
It is simply a convienient way to measure in chemistry
because one mole of atoms is equal to the average atomic mass of that
element in grams.
This is the definition of molar mass, molecular mass or
mass. With this idea we are able to measure the mass of a
and "count" how many atoms are present. The "representative
that we use most often with a mole are atoms (representative particles
elements), formula units (representative particles of ionic compounds)
molecules (representative particles of covalent compounds).
Be able to solve problems using scientific notation and dimensional
analysis (the factor-label method).
Unit VI Chemical Quantities
Be able to solve problems using the concepts of a mole, molar mass and
Be able to solve problems using molarity and percents.
Be able to calculate percent composition of compounds.
Be able to calculate Empirical and Molecular Formulas.
Be able to determine the percent of water in a hydrate.
Terms: molecular mass, formula mass, molar mass, mole,
Avogadro constant, molarity, percent composition, hydrate
Important people of history: Avogadro
Suggested Problems: Read Chapter 7 and Chapter 13, Section 2
pg 233 (1-13) pg 240 (8-12) pg 248 (4-8) pgs 251-256 (1-3,
14, 16-18, 22-58, 62-84) pg 467 (2-12) pgs 488-492 (47-61)
Return to the HHS Science Home Page
History of the mole
National Mole Day Org