Be respectful – no electronics please! Announcements Exam scores posted late tonight! Get graded exams back tomorrow in discussion. Pre/post lecture assignments due as usual Tuesdays & Thursdays at 8:00 am Workshop in lab on Monday (completion credit) Bring a textbook to class on Monday!

Most Missed Question (55% Missed)

Consider a substance, which can exist in multiple phases: in terms of particle movement… Which phase has highest energy? A solid A liquid A gas All the same Which phase is most stable? A solid A liquid A gas All the same

Clicker #1 Is a racquetball frozen by liquid nitrogen an endothermic or exothermic process? (The system is underlined.) A) endothermic B) exothermic

Clicker #2 Is the boiling of water an endothermic or exothermic process? (The system is underlined.) A) endothermic B) exothermic

Clicker #3 Ba(OH)2·8H2O(s) + 2NH4SCN(s)  Ba(SCN)2(aq)+ 2NH3(g)+ 10H2O(l) Is the reaction of the two solids in the beaker an endothermic or exothermic process? A) endothermic B) exothermic

Clicker #4 Which is lower in potential energy? H2/O2 or H2O A) H2/O2 B) H2O

Clicker #5 Which is more stable? H2/O2 or H2O A) H2/O2 B) H2O

Overall goal: Atomic Structure Chemical Bonding 3D Molecular Structure Molecular Properties