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Lecture 1: Thermodynamics review.ppt

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					                         Statistical Thermodynamics




Lecture 1: Thermodynamics review


            Dr. Ronald M. Levy
        ronlevy@lutece.rutgers.edu
                                                Chemical Physics: Statistical mechanics


  Chemical Physics:
  explain microscopic properties based on the properties of individual
  molecules and molecular interactions

  Statistical Mechanics:
                              Statisitical Mechanics
            Microscopic                                   Macroscopic




        Atom       Molecule                              Thermodynamics

  Themodynamics:
  Mathematical relation between experimental properties of macroscopic systems


                                                   volumetric thermal    Isothermic compressibility
                                                   expansion coefficient coefficient
MQ. Chapter 1                                                                             1
The three laws of thermodynamics




                        2
                                                    Thermodynamic Potential


Thermodynamic Potential:
The differential form of first law of thermodynamics
                                                              E (S, V)
dE = dQ – dW = TdS – pdV
      Independent
                                    Thermodynamic Potential
        Variable

       (S, V)                 Internal energy            E (S, V)
                              Helmholtz free
       (T, V)                                            A (T, V)
                                    energy
       (T, p)              Gibbs free energy             G (T, p)

       (S, p)                        Enthalpy            H (S, p)
                       Done by Legendre transform                        3
                                                    Legendre transformation


 Legendre Transforms:                                                y(x)
                                                   P2 = dy/dx @(x2,y2)



                                         P1 = dy/dx @(x1,y1)
      y(x)              Ψ(P)
                                              Ψ1
Relation between the tangent and the
intercept at any point on the function              Ψ2 (intercept)




       How do we find the inverse Legendre
       transforms?

                                                                            4
Application of Legendre transform




      Legendre transform




                             5
                                                                   Maxwell Relations


    Maxwell Relations and Thermodynamic square:
                                                                      Thermodynamic square
                                                                      V        F        T
           V                                                 T


V      T
           S     P    Symmetric means +   S                  P        E                    G
           S                                                 V
S      P                                                              S        H           P
                      Asymmetric means
           P      T   -                   P                  T

                               G              Gibbs free energy


                                               1st Derivative
                          V         S          Equation of state


                                                  2st Derivative
                                                  Maxwell relations

                                                                                       6

				
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posted:1/14/2014
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