Chapter 8
Mole Conversions
Part 2
3.2: Molecular Mass/Weight
Formula Mass/Weight
•The formula of an Acetylsalicylic
Acid (Aspirin) molecule is C9H8O4
•Acetylsalicylic Acid (Aspirin) has
molar mass of 180.159 g/mol
•How many hydrogen atoms are
contained in a 0.372 g tablet?
0.372g C9H8O4
0.372g C9H8O4
mol
180.159 g
0.372g C9H8O4
mol
180.159 g
6.02 x 1023 molecules
mol
0.372g C9H8O4
mol
180.159 g
6.02 x 1023 molecules 8 H atoms
mol
molecule
0.372g C9H8O4
mol
180.159 g
6.02 x 1023 molecules 8 H atoms
mol
molecule
= 9.94 x 1021 H atoms
What is the mass in grams of one atom of carbon?
What is the mass in grams of one atom of carbon?
12.0 g/mol
What is the mass in grams of one atom of carbon?
12.0 g
mol
What is the mass in grams of one atom of carbon?
12.0 g
mol
mol
6.02 x 1023 atoms
= 1.99 x 10-23 g/atom
What is the mass in grams of one molecule of water?
What is the mass in grams of one molecule of water?
18.0 g
mol
What is the mass in grams of one molecule of water?
18.0 g
mol
-23 g/molecule
=
2.99
x
10
mol
6.02 x 1023 molecules
Information for Upcoming Mole Quiz
• How does a mole relate to particles and mass?
(example: One mole of H2O is 6.02 x 1023 H2O
molecules and has a mass of 18g).
• Be able to use this information in factor-label
problems.
• Know how to determine the number of atoms in a
molecule. Be able to use this information in factorlabel problems.
• Be able to determine the number of grams/molecule.
• Identify the diatomic gases.
• Do metric conversions.
Homework
• Mole Worksheet (#1-20)
• Notice that answers are provided for this
worksheet in your notebook.