1. To Do… OWL Lectures Discussion Chapter 10 due Friday, March 30
Today: Sections
Thursday: start reading Chapter 11
Discussion
Chapter 10 and Chapter 11 text homework

2. Big Ideas – Discussed All matter is made up of atoms.
Atoms are in constant motion (kinetic molecular theory).
Chemical reactions are re-arrangements of atoms (substances change into other substances).
Vinegar and sugar dissolving in water demo

3. Big Ideas – To Be Discussed
Chemical changes are accompanied by energy changes.
At the same conditions, some substances are liquids, some are solids, and others are gases.
Atoms have structure.
Water vs liquid nitrogen

4. Questions to Consider:
Why are there molecules?
Why are there phases of matter?
Why does water, for example, have the properties that it does?
Water vs liquid nitrogen

5. Overall goal: Atomic Structure Chemical Bonding 3D Molecular Structure
Molecular Properties

6. Clicker Question
Which is lower in potential energy? Which is more stable?
H2/O2 or H2O
Lower PE More Stable
A) H2/O2 H2O
B) H2O H2/O2
C) H2/O2 H2/O2
D) H2O H2O

7. Big Ideas – Energy
A system is more stable with lower potential energy.
Achieving low potential energy is a driving force.
Thus, if energy is transferred into a system, the system will work to transfer this energy out.
Water vs liquid nitrogen

10. Clicker Question
A racquetball is frozen by liquid nitrogen. Label each process as endothermic or exothermic. (The system is underlined.)
Racquetball Liquid Nitrogen
A) Endothermic Endothermic
B) Exothermic Endothermic
C) Endothermic Exothermic
D) Exothermic Exothermic