1. Lon-Capa 4th HW assignment due Friday, 10/7, 5 pm. It is open now.
3rd Quiz due Sunday, 10/9 by 10 pm. It will open Friday, 10/7 at 5 pm.
5th HW assignment is also open!
Three new videos (for Section 9.3). Please watch by Friday.

2. Hess’s Law Due to first law and H being a state function.
If a reaction is reversed, the sign of H is also reversed
The magnitude of ΔH is directly proportional to the quantities of reactants and products in a reaction.
That is, if the coefficients in a balanced equation are multiplied by an integer, the value of H is multiplied by the same integer.

3. Clicker Question Given the following data
2NH3(g)  N2(g) + 3H2(g) H = 92kJ
2H2(g) + O2(g)  2H2O(g) H = -484kJ
Determine ΔH for
2N2(g) + 6H2O(g)  3O2(g) + 4NH3(g)
a) kJ
b) kJ
c) kJ
d) kJ
e) I did not/cannot get any of these answers.

4. Pathway for the Combustion of Methane

5. Schematic Diagram of Energy Changes

6. Chapter 9: Problem #117
This problem is an application of Hess’s law, although it may not be obvious upon reading it.