1. CHEM 433 - 10/13/11 III. 2nd Law of THERMO
• Intro & Overview ( )
- 2nd Law Statements
- Using it: SSYS vs. SSURR
(this is the hard way…)
READ: CHAPTER 3
HW #5 Due Monday
Web is up-to-date, including review sheet (will post HW#4 key late tomorrow or M)

2. 1ST LAW:. What can happen. (permissible changes) • ΔU = q + w
1ST LAW: What can happen? (permissible changes) • ΔU = q + w or dU = dq + dw • The work needed to change an adiabatic system is the same, regardless of how the work is performed (wad = ΔU). • Energy is conserved. It is neither created nor destroyed. • “You can’t get something for nothing!”

3. 2ND LAW:. What does happen
2ND LAW: What does happen? (spontaneous changes) • No process is possible in which the sole result is absorption of heat from a reservoir and its complete conversion to work. (Kelvin, Planck) • Heat can not be conveyed from a lower temperature reservoir to a higher temperature reservoir, without the performance of work. (Clausius) • The ENTROPY of an isolated system increases in the course of spontaneous change (Stot > 0). • You can convert all your work into heat – but you can’t convert all your heat into work. —> “You can’t even break even!”