1. Basic Principles of Chemistry
Unit 2: Chemical Reactions and Their Significance
Lecture #8

2. Classifying Matter

3. Molecules vs. Compounds
Molecule—two or more atoms joined together in a fixed ratio

4. Molecules vs. Compounds
Compound—two or more different atoms joined together in a fixed ratio

5. Molecules vs. Compounds
When is a molecule NOT a compound?

6. Classes of Pure Substances

7. Molecular Elements The following are molecular elements:
Hydrogen (H), nitrogen (N), oxygen (O), fluorine (F), chlorine (Cl), bromine (Br), iodine (I), phosphorus (P) and sulfur (S)

8. Metals and Nonmetals Nonmetals generally combine with
other nonmetals to form molecular compounds
metals to form ionic compounds
Metals generally combine with
nonmetals to form ionic compounds

9. The Periodic Table
Let’s take a spin around the periodic table...

10. Mass Ratios vs. Atom Ratios
What is the ratio of oxygen atoms to carbon atoms in carbon dioxide (CO2)?
What is the ratio of oxygen mass to carbon mass in carbon dioxide?
What are these values for H and O in water (H2O)?

11. The Anatomy of a Chemical Formula
H2O CO2 CO C6H12O6
CuSO4.5H2O Al2O3

12. Formulas of Ionic Compounds
Write the formula of the salt made between barium cation (Ba2+) and chloride anion (Cl-)
BaCl2

13. Formula Mass of Compounds
Sum of the atomic masses of all of the atoms in the compound

14. Formula Mass of Compounds
What is the formula mass of water (H2O)?
18.02 amu

15. Formula Mass of Compounds
What is the formula mass of an ionic compound formed by combining calcium ions with chlorine sulfide ions?