# 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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