3. Thermodynamics A Garvey/Ziemba Production

4. Specific Heat Capacity  The Heat (energy) required to produce a certain temperature per gram of material  Specific Heat = heat supplied (mass of object) (Temp Change) OR C = q/(m)(∆T) -> q = MC∆T T is in Kelvin, mass in grams, q in Joules. Specifics Heats are often given in problems

5. Changing States Calculated by Energy = Heat of Fusion/Vaporization x mass of substance This is so easy even JC can do it!! Lets try it!

6. Sample Problemo  How much heat is required to warm 500g of a solid teacher at -50 o C to steam at 200 o C? (Teachers are made only of H 2 O) heat of fusion = 333.5J/g, Vaporization = 2256J/g. specific heat capacities, in order of solid, liquid, gas, hinton, are 2.1, 4.2, and 2.0 J/g x K Lets go!

7. We can do this….together!  It starts at -50 o C and goes to 0 o, a change of 50 o K  So (500g)(2.1J/gxK)(50 o ) = 52,500 J  Next for Ice -> water, (500g)(333.5J/g) = 166,750J  Water at 0 o to 100 o -> (500g)(4.2J/gxK)(100 o K) = 210,000J  Now for Water -> Steam (500g)(2256J/g) = 1,128,000J !!  Finally, Steam at 100 o C to 200 o C -> (500g)(2.0J/gxK)(100 o K)=100,000J  Add them up -> 52,500 + 166,750 + 210,000 + 1,128,000 + 100,000 and we get….  1657kJ of Death!!!

8. What we just did looks like this, with 5 steps

9. Enthalpy change …(BORING!!!!)  The heat transferred into or out of a system (constant pressure)  Enthalpy change is Hproducts - Hreactants  Just remember products minus reactants. It works every time, no matter what unit you are studying. Don’t listen to Mr. Hinton telling me im wrong.  Enthalpies of reaction are the same!!! Sum of the products enthalpys minus sum of the reactants…every time, it works….

10. The Hess Family Fund  Also know as Hess’s Law  Basicly, if you add reactions, the sum of the reaction’s ∆H’s is the new reaction’s ∆H  If you reverse an equation, the sign on ∆H must change  If you multiply equation, multiply ∆H by same number  Helpful Hint: for all reactions, g = 9.8m/s 2

11. Random

12. Entropy, Free Energy  The measure of Disorder (symbol is S)  !!! ∆S is Sum of S products - Sum of S reactants  G stands for Gibbs Free Energy, another lovely Thermodynamic Function  ∆G = ∆H - T ∆S  This is Gibb’s Lovely Free Energy Equation. It is (so says the book) very important

13. Little More Free Energy  ∆G(reaction) = Sum∆G(products) - Sum ∆G reactions  Well I know im surprised  I’d also like to take this time to remind you all the exothermic is a negative ∆H and endothermic is a positive ∆H  Better Late than never, you know

14. Ther MO and the E constants  We all know the old saying  “∆G = -RT ln K!”  R is 8.314  K is the THERMODYNAMIC Equilibrium CONSTANT  But hey!  If K>1 Products are favored in a reaction  If K = 1 (Rare) Its at equilibrium  If K < 1 Reactants are favored.  You, Zev and Pat, are never favored.

15. The Last tired, slide.  Give us a good grade  Give John money  All your Base are belong to the Chemistry Department, in containers kept apart from Acids and Nick’s small thieving hands