HAHS
MS. KNICK
Avogadro, The Mole, and
Grams
The Mole
 The amount of substance
that contains as many
particles as there are
atoms in exactly 12 g of
carbon.
 We can think of the mole is
a counting unit for
chemists.

Examples:


1 dozen =12
1 ream of paper = 500 sheets
Avogadro’s Number
 Is the number of particles in exactly one
mole of a pure substance.
 6.02 x 1023 is called “Avogadro’s Number” in
honor of the Italian chemist Amadeo
Avogadro (1776-1855).
I didn’t discover it. Its
just named after me!
Avogadro’s Number (con’t)
 There is 602000000000000000000000
atoms in 1 mole of a substance
THAT’S A GIGANTIC NUMBER!!!!!!!!!
Molar Mass
 Is the mass of 1 mole of
a per substance
 Has units of grams per
mole (g/mol)
 Equaled to the atomic
mass of the element or
compound.
Molar Mass of a Compound
 Add up all the masses of each type of atom in the
compound.
 Example: Molar Mass of Ca(OH)2
Ca: 1 x 40 = 40
O: 2 x 16 = 32
H: 2 x 1 = 2
The molar mass is the
sum (40 + 32 + 2) which is
equaled to 74 g/mol
Molar Mass
 Is the mass of 1 mole of
a per substance
 Has units of grams per
mole (g/mol)
 Equaled to the atomic
mass of the element or
compound.
Calculations:
Converting moles to grams
 Given # of mole X g (look at periodic table)=
1 mole
g of
 How many grams of lithium are in 3.50
moles of lithium?
 3.50 mole X 6.941 g = 24.29 g Li
1 mol
Calculations:
Converting grams to moles
 Given # of g X
1 mol =
mol of
g (look at periodic table)
 How many moles of lithium are in 18.2
grams of lithium?
 18.2 g X 1 mol Li = 2.622 mol Li
6.941 g
Calculations:
Converting Moles to Particles
 Given # of mol x 6.02 x 1023 part=
atoms
1 mol
 How many atoms/particles/molecules of lithium
are in 3.50 moles of lithium?
 3.50 mole X 6.02 x 1023 = 2.11 x 1024 atoms of Li
1 mol
Calculations:
Converting Particles to Moles
 Given # of particles x 1 mole =
mol
6.02 x 1023
 How many moles of lithium are there in
1.2044 x1024 particles of Li?
 1.2044 x 1024 part x 1 mole
= 2.0 mol Li
6.02 x 1023 part
Calculations:
Converting grams to particles
 Given # of grams x 1 mol x 6.022 x 1023=
particles
?g
1 mol
 How many atoms/particles/molecules of lithium
are in 18.2 g of lithium?
 18.2 g x 1 mol x 6.022 x 1023 = 1.58 x 1024 particle Li
6.941g
1 mol
Calculations:
Converting particles to grams
 Given # of particles x 1 mol
x
?g=
g
6.022 x 1023 1 mol
 How many grams are there in 8.02 x 1025 particles
of lithium?