1. WARM UP
Think back to the our thermodynamics unit. In any exothermic reaction, lots of heat is created quickly, and the reaction creates lots of entropy. What is entropy?

2. The Big Bang Theory

3. Entropy
Chemistry II

4. Entropy (S) A measure of disorder/randomness
More disorder, higher entropy
Universe tends to move toward greater entropy

5. Entropy (S) Microstates (probable arrangements) Ludwig Boltzmann
The more microstates, the higher the entropy

6. Second Law of Thermodynamics
The entropy of the universe increases in a spontaneous process
Decreases in a non-spontaneous one

7. Entropy Calculations Standard entropy From known data – Appendix 3
Δ Srxn = Sproducts – Sreactants
Unit is J/K·mol

8. Entropy Calculations Entropy and Energy
Δ Suniverse = Δ Srxn + -(Δ E)rxn
Heat production increases entropy

9. Third Law of Thermodynamics
The entropy of a perfect/pure crystalline solid is zero at a temp of 0 K (absolute zero)
Perfect order

10. Third Law of Thermodynamics
Allows for standard entropy calculations
Δ S = Sfinal – 0

11. WRAP UP Predict the entropy change for the following:
Burning gas in your car
Melting ice
Locker clean-out day

12. WARM UP
Define entropy.
Explain the second law of thermodynamics. Why does the universe work this way?

13. (remember that you need to factor stoichiometry into your equation)
WRAP UP
Use the standard entropies to calculate the standard entropy of: H2(g) + ½ O2(g)  H2O(l).
(remember that you need to factor stoichiometry into your equation)