The Mole Worksheet
Think of moles as a "chemist's dozen". Just as 12 eggs is a dozen eggs,
6.02 × 1023 eggs is a mole of eggs. 6.02 × 1023 molecules of oxygen is a
mole of oxygen.
The number of grams in a mole is different from substance to substance.
If you're like most students, it's this that's confusing you. You can find the
number of grams by looking on the periodic table. Just look at the
atomic mass of the element.
A mole is a standard scientific unit for measuring large quantities of very small entities such
as atoms, molecules, or other specified particles. The mole designates an extremely large number of units,
6.02214179 × 1023, which is the number of atoms determined experimentally to be found in 12 grams
of carbon-12. Carbon-12 was chosen to serve as the reference standard of the mole unit for the International
System of Units (SI).
Example 1: Find the Molar mass
Elements/Compounds
Fe
Cl
KOH
BF3
Mg(OH)2
Relative atomic Mass (Refer to the
Periodic table)
Molar Mass (weight of 1 mole)
Example 2: Convert 4.875 moles of oxygen gas into atom
Number of
Moles (n)
Number of
Atoms/Particles/
Molecules (N)
Example 3: Convert 78g of oxygen gas into moles
Mass (m)
Grams
Number of
Moles (n)
Example 4: Convert 78g of oxygen gas into atoms
Mass (m)
Grams
Number of
Moles (n)
Number of
Atoms/Particles/
Molecules
(NA)