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

Higher temp: more “spread”

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.

Spontaneous or Not?

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!

A Question to Consider Calculate S and Suniv when 50.0 g of ice at 0C is dropped into 100.0 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.