1. To Do 5th HW assignment due Friday by 10 pm.
Quiz tomorrow in Discussion.
Continue reading Chapter 6: we will finish Chapter 6 Thursday.

2. Heat is motion

3. Temperature: measure of KEavg

4. Clicker Question
The following chemical reaction releases heat: A2 + B2  2AB. This means:
more stable higher average bond energies
a) Reactants Reactants
b) Reactants Products
c) Products Products
d) Products Reactants
e) I do not know.

5. Exothermic Process

6. Endothermic Process

7. Clicker Question The freezing of water is an ________ process.
a) exothermic
b) endothermic
c) I do not know.

8. Thermodynamics vs. Kinetics

9. Some Big Ideas Low energy  low in potential energy  more stable.
If a system absorbs energy, the natural tendency is to release it.
That is, achieving low potential energy is “natural”.
Ground state preferred over excited state.
Energy is converted from one form to another but is NOT created nor destroyed.
First law of thermodynamics.
Energy is a state function (heat and work are not).

10. Determining Hrxn
Since H = qp, determine the heat transferred at constant pressure. This is termed calorimetry.
Since energy is conserved, we can often determine Hrxn for one reaction given values of Hrxn for others. Uses the principle in Hess’s Law.
Use standard enthalpies of formations for reactants and products (we have tables of these).