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Unformatted text preview: 1 Homework Hint Problem 3.3 ? s s e  = = p 1 1 s s e e  = = p p Geometric series: 1 n n a ar r = = For 0< r < 1 Last Time Boltzmann factor Partition Function Heat Capacity The magic of the partition function 2 Last Time Reversible process slow enough to remain in equilibrium the whole time Pressure Thermodynamic Identity Thermodynamically conjugate variables You can control one or the other but not both Helmholtz Free Energy Differential of Free Energy Maxwell Relations Free Energy and the Partition Function Quantum Concentration Ideal Gas Equipartition of Energy Entropy of Mixing Today Chapter 3 (part 2) Free energy, ideal gas 3 Intensive and Extensive Variables + = Intensive Variables : Dont scale with the size of the system Extensive Variables: Scale with the size of the system Intensive and Extensive Variables Conjugate Pairs: One is intensive, the other is extensive. + = Extensive Intensive 4 Internal Energy Note that for the internal energy U, the variables are the extensive ones: This is the right energy to talk about if entropy and volume are held constant. But thats kind of hard its easier to hold temperature constant. Helmholtz Free Energy Why a new energy? Its the right thing to use when V, are constant. The Helmholtz free energy, rather than internal energy, is minimized for thermodynamic processes at constant V and . Takes into account that entropy wants to maximize. This is the available work (useful energy, or free energy) when V, are constant. 5 Differential of the Helmholtz Free Energy Thermodynamic Identity: product rule These are the right variables for F Helmholtz energy: Legendre Transforms We can do similar things with ( p,V ), and use the Gibbs Free Energy, for systems held...
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This note was uploaded on 12/14/2010 for the course PHYSICS 416 taught by Professor Savikhin during the Spring '10 term at Purdue UniversityWest Lafayette.
 Spring '10
 SAVIKHIN
 Physics, Energy, Work, Heat

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