Statistical Physics

Question 1

What is a macrostate?

Answer 1

A thermodynamic state of the system described by macroscopic functions of state such as Temp, Pressure, Volume.

Question 2

What is a microstate?

Answer 2

A specific quantum state of the system(not of a single particle).

Microstates specify all relevent information of all particles, spim, position, energy, velocity etc.

Question 3

What does PEAP or PEEP (Peep probably better to use) mean?

Answer 3

PEAP- Principal of Equal A Priori Probability

PEEP- Principal of equal equilibrium probability.

Question 4

What does PEAP/PEEP state?

Answer 4

PEEP states that when an isolated system reaches equilibrium, all microstates accessible to it are equally probable.

Question 5

What does the Boltzmann equation show?

Answer 5

Shows the relationship between entropy and the number of ways the atoms or molecules can be arranged in a thermodynamic system.

Question 6

State the Boltzmann equation and its meaning

Image shown on this side is another imortant variation of equation/shows how the W component is used rather than probability, p.

Answer 6

The boltzmann equation is a probability equation relating entropy S to W, the number of real microstates corresponding to the Gas’s macrostate.

IF DEALING WITH PROBABILITIES USE
S = Kb * ln (P)i

Question 7

If the number of particles, N, and the number of macrostates, M, is known, how do you find the number of microstates?

Answer 7

Question 8

Example problem

Answer 8

Question 9

Derivation of statistical temperature

Answer 9

Question 10

Joule expansion entropy change calculation

Answer 10

Useful info on entropy and probability:

(context)

• Suppose a number of macrostates share the same energy and are therefore mutually accessible.
• Let W1, W2, … represent the number of microstates available for each of those macrostates.
• According to PEAPP, the system has a prob, Pi to be in the i-th microstate.