1. As always… OWL Lon-Capa assignments Lecture videos Textbook Read
Do text homework

2. Clicker Question
The following chemical reaction is exothermic: 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.

3. Clicker Question Use the following data for methanol (CH3OH):
ΔHfusion = 3.18 kJ/mol at –97.6°C
ΔHvaporization = 35.3 kJ/mol at 64.7°C
Determine ΔE (kJ/mol) for methanol freezing at –97.6°C.
a) b) – c) d) e) –3.18

4. Clicker Question Use the following data for methanol (CH3OH):
ΔHfusion = 3.18 kJ/mol at –97.6°C
ΔHvaporization = 35.3 kJ/mol at 64.7°C
Determine ΔE (kJ/mol) for methanol vaporizing at 64.7°C.
a) b) c) –35.3 d) e) –38.1

5. Determining Hrxn
Since H = qp, determine the heat given off or required at constant pressure by measuring temperatures. 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).

6. A Coffee-Cup Calorimeter Made of Two Styrofoam Cups

7. Bomb Calorimeter (constant V)