Molar Mass!
Chapter Ten
Chemistry
Mrs. Luckett
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
Anticipation guides
Molar Mass
It equals how many grams are in one mole
of an element or compound
 Examples:




Element: Na molar mass is 22.990 grams
Compound: NO molar mass is 30 grams
Use the subscript numbers to get your total

H2O = H is 1.0079 x 2 = 2.0158
O is 15.999 x 1 = 15.999
Molar mass =
Calculating molar mass with
parentheses

When there are parentheses you have to multiply
the subscript number on the outside by the subscript
on the inside.

Example: Mg(NO3)2
Mg = 1 x 24.305 grams = 24.305
N = (2 x 1) x14 grams = 28
O = (3 x 2) x 16 grams = 96
Total = ____ grams
Practice Problems
1)
What is the molar mass of the following
compounds?
FeO
2)
Li3PO4
3)
P(NO2)3

Single Step Conversions
Luckett
Chemistry
Conversion factors

You need to create two conversion factors
for each equal quantity



1 mole
OR
molar mass
1 mole
OR
22.4 L
1 mole
6.02 x 1023 particles
molar mass
1 mole
22.4 L
1 mole
6.02 x 1023 particles
1 mole
Example: what are the two conversion factors for
the molar mass of LiNO3?
Victor and Alec was here
Converting moles to mass and
mass to moles

To convert moles to mass you have to multiply by
the molar mass
_____ moles

x
molar mass
1 mole
To convert mass to moles you have to divide by the
molar mass
_____ grams x
1 mole
molar mass
Practice Problems

Knowing the molar mass convert the
following mole quantities to grams.
1)
0.98 moles FeO
2)
234 grams Li3PO4
3)
7.56 moles P(NO2)3
Converting Particles to Moles
and Moles to Particles

To convert moles to the number of particles you
have to multiply by avogadro’s number
_____ moles

x
6.02 x 1023 particles
1 mole
To convert the number of particles to moles you
have to divide by avogadro’s number
_____ particles x
1 mole
6.02 x 1023 particles
Practice Problems
Convert between moles and particles.

0.98 moles FeO

2.34 x 1025 particles Li3PO4

7.56 moles P(NO2)3
Converting Volume to Moles
and Moles to Volume

To convert moles to volume you have to
multiply by 22.4 L
_____ moles

x
22.4 L
1 mole
To convert volume to moles you have to
divide by 22.4 L
_____ Liters x
1 mole
22.4 L
Practice Problems
1)
Convert the following mole quantities to
Liters.
2)
0.98 moles FeO
3)
234 Liters Li3PO4
4)
7.56 moles P(NO2)3