1. Announcements Lon-Capa: 5th HW assignment due Friday 10/21 by 5 pm.
Lon-Capa: 4th Quiz due Sunday, 1023 by 10 pm. Opens Friday 10/21 at 5 pm.
Exam 2 is Tuesday, October 25; rooms the same as Exam 1; equation sheet posted online.
Office hours Tuesday: 1 pm, not 10 am

2. Higher temp: more “spread”

3. Clicker Question
Consider the process: H2O(g)  H2O(l). Are Ssurr and S thermodynamically favorable or unfavorable?
Ssurr S
a) favorable favorable
b) favorable unfavorable
c) unfavorable favorable
d) unfavorable unfavorable
e) I do not know.

4. Spontaneous or Not?

5. Characteristics of Ssurr
The sign of Ssurr depends on whether the reaction or process is exothermic (Ssurr >0 or “favorable”) or endothermic (Ssurr < 0 or “unfavorable”).
The magnitude of Ssurr depends on the temperature.
To increase the effect of Ssurr , lower the temperature.
To decrease the effect of Ssurr , raise the temperature.
LeChatelier’s principle!

6. A Question to Consider
Calculate S and Suniv when 50.0 g of ice at 0C is dropped into g of water at 75C in a perfectly insulated vessel and briefly discuss these numbers to show that all of the ice will indeed spontaneously melt.
Hfusion for ice is 6.02 kJ/mol at 0C and Cp for water is 75.3 J/Kmol
Assume Cp is constant over the temperature range in question.