Chemistry Notes: What is Molar Mass?
* Remember: atomic mass (g) – mass in grams of 1 mole of the element
Molar Mass
(MM)
=
___grams____
1 Mol
Let’s examine periodic table!
If I had one mole of _____ it’s molar mass would be _______ g per 1 mol.
Carbon
MM= 12.0 g / mol
(not diatomic) Atomic Hydrogen
MM= 1.0 g / mol
Mercury
MM= 200.6 g / mol
Iron
MM=55.8 g / mol
Sulfur
MM= 32.1 g / mol
How many particles do these elements contain?
AVOGADROS NUMBER:
1 mol of anything = 6.02 X 1023 atoms
How do you calculate the Molar Mass of compounds?
You use the formula for that compound. Let’s see!
MM= grams/mol
EX. Sulfur Trioxide
Chemical Formula = _____________
How many total atoms make up one molecule? Atoms = _____________
S: ___ x ______ =
O: ___ x ______ = _________ +
The molar mass of sulfur trioxide = _______ grams per ________
EX. Phosphorus Trichloride
Chemical Formula = __________
How many total atoms make up one molecule? Atoms = _____________
P: ___ x ______ =
Cl: ___ x ______ = _________ +
EX. Sodium Hydrogen Carbonate
Chemical Formula = __________
How many total atoms make up one molecule? Atoms = _____________
Na: ___ x ______ =
H: ___ x ______ =
C: ___ x ______ =
O: ___ x ______ = _________ +
Covalent Compounds are made up of _____________.
Ionic Compounds are made up of _______________.
Elements are made up of _____________.
Now let’s use Molar Mass to find other measurements!
MOLE  Mass Conversions
And
MASS  Mole Conversions
Use your Road Map!
Book pg. 298
Ex. #1 Write the chemical formula for aluminum oxide ___________
What is given? _________ Trying to find? ____________
______________ x _______________ =
g of
Ex. #17 Write the chemical formula for iron (II) hydroxide ___________
What is given? _________ Trying to find? ____________
______________ x _______________ =
g of
Ex. #18 Write the chemical formula for boron ___________
What is given? _________ Trying to find? ____________
______________ x _______________ =
g of
VOLUME  Mass Conversions
And
VOLUME  Mole Conversions
Use our Mole Road Map!
Book pg. 301
At STP (Standard Temp and Pressure): Get out Reference Table pg. 1
1 mole of gas = 22.4 L of gas = 6.02 x 1023 particles of gas
Problem 10.7
What is the correct formula for sulfur dioxide? _____
What is given? ___________
Trying to find? _________
______________ x _______________ =
Problem 10.8 pg. 302
What is given? __________
L of
Density = __________ = ________
Trying to find? ___________
#18 HINT: Density = __________ = ________
What is given? __________
Trying to find? ___________