Lecture 1 ： Thermodynamics review

Dr. Ronald M. Levy

ronlevy@temple.edu

Statistical Thermodynamics

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

Chemical Physics: Statistical mechanics

Statistical Mechanics:

Microscopic MacroscopicStatisitical Mechanics

Atom Molecule Thermodynamics

Themodynamics:Mathematical relation between experimental properties of macroscopic systems

1

Isothermic compressibility coefficient

volumetric thermal expansion coefficientMQ. Chapter 1

The three laws of thermodynamics

2

3

Thermodynamic Potential:The differential form of first law of thermodynamics

dE = dQ – dW = TdS – pdV

Thermodynamic Potential

E (S, V)

(S, V)

(T, V)

(T, p)

(S, p)

Independent Variable

E (S, V)

A (T, V)

G (T, p)

H (S, p)

Thermodynamic Potential

Internal energy

Helmholtz free energy

Gibbs free energy

Enthalpy

Done by Legendre transform

Legendre transformation

4

Legendre Transforms: y(x)

P1 = dy/dx @(x1,y1)

Ψ2 (intercept)

P2 = dy/dx @(x2,y2)

Ψ1

y(x) Ψ(P)

Relation between the tangent and the intercept at any point on the function

How do we find the inverse Legendre transforms?

Application of Legendre transform

5

Legendre transform

Maxwell Relations

6

V

S P

TF

G

H

E

Maxwell Relations and Thermodynamic square:Thermodynamic square

V T

PS

V

PS

T

PSSymmetric means +

S

TP

V

TPAsymmetric means -

G

V S

Gibbs free energy

1st DerivativeEquation of state

2st DerivativeMaxwell relations