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

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.

The meaning of Grxn At constant temperature and pressure the sign indicates the spontaneity of the reaction. Grxn < 0 means spontaneous Grxn > 0 means not spontaneous (or spontaneous in the opposite direction) If we change the temperature we can change the sign of Grxn The magnitude of Grxn tells us the relative extent of the reaction (recall that K does too!) If we change the temperature we can change the magnitude of Grxn.

Clicker Question Consider the spontaneous reaction: 2KClO3(s)  2KCl(s) + 3O2(g) Is the reaction endothermic or exothermic? a) Endothermic b) Exothermic c) More information is needed. d) I do not know how to answer this question.