1. Chem
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Today: Introduction to the Mole

2. Molar Mass: The mass of one mole of a substance
Percent Composition: Identifies the elements present in a compound as a mass % of the total compound mass

3. 41.67% Mg
54.86% O
3.46% H
47.70 % Cr
52.30 % F
15.77% Al
28.11% S
56.12 % O
38.67% K
13.86% N
47.47% O
58.33 grams
grams
grams
grams

4. How to Convert between Grams and Moles:
1 mol H3PO4
0.306 moles H3PO4
98 g H3PO4

5. Grams <-> Moles Conversions

6. Atom vs. Molecule ATOM MOLECULE
Atom= the smallest, simplest unit of matter.
Can refer to individual elements only
Molecule=the smallest, simplest unit of a pure substance
Can refer to elements or compounds
ATOM H H H H H
MOLECULE
MOLECULE

7. ATOM MOLECULE H H H H H MOLECULE
A water molecule is represented by H2O
A water molecule contains 2 atoms of hydrogen and 1 atom of oxygen
A hydrogen molecule is represented by H2 (it’s diatomic)
An oxygen molecule is made up of 2 hydrogen atoms

8. Remember:
1 mole = 6.02 x 1023 particles!

9. Converting between grams and molecules
1 mol C3H5N3O9
6.02 x 1023 molecules C3H5N3O9
g C3H5N3O9
1 mol C3H5N3O9
=1.51x 1024 molecules C3H5N3O9

10. Molecules Conversions
1.51 x 1024 molecules
4.37 x 1023 molecules