Statistical Thermodynamics

Introduction to terms

Entropy : Atomic Scale Disorder

Gibbs : Degree of mixed upness at atomic/molecular scale

Entropy solid less than liquid less than gas

Latent heat : Hidden Heat (Latent Heat applies when melting / vaporizing)

Entropy change when melting an ice cube : delta Hm/Tm

For the process to occur spontaneously, the entropy of universe should increase . Delta S universe = Delta S system + Delta S surrounding

Entropy of the universe equal to zero in this case

Concept of microscopic

Energy level depends on volume

If Volume is fixed, energy level is fixed

Example : Energy level should be fixed, but the number of atoms may vary. The most random arrangement is the most likely to occur, since it's the most probable

Using combination formula

WHen Entropy is maximum

tHe number of arrangement is also in its maximum value

Influence of Temperature

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Determination of the most probable state

Fixed Volume - Fixed Energy Level

Fixed internal energy, U = niEi + n1+E1 = sigma ni Ei

At equilibrium, the atoms should be in the most random arrangement

Using the combination formula, and Langrange Multiplier method, we get Ni, from ln (x) formula we get a formula involving partition and internal energy. The value of beta is. 1 over ( boltzman constant*temperature) from boltzman equation of entropy

Heat Flow and Production of Entropy