# Section A Flashcards

## Understand the concepts of micro states, configurations and macro states and, in particular, the idea of the predominant configuration

Why is statistical thermodynamics useful?

Helps us to predict values of the change in gibbs free energy and equlibrium constants for all reactions

Distinct particles

You can tell which particle is which, i.e. they can be labelled.

Microstate

- specifies each individual particle in the system and where they are in the system (energy level) at any instant of time
- not direcltly observed

configuration

- specifies how many particles are in which energy level at any instant of time
- not directly observed

Macrostate

- what we observe in experiments (E, S, H, V and T)
- many microstates contribute to the macrostate and many microstates are visited over the course of an experiment, or simulation

individual particles

have states (energy levels) with energies, E0, E1…

Instantaneous configuration

At any instant there will be x number of particles with corresponding energy, e.g. x1 has E1

Equal a priori Probability of configuartions

- Configurations do noat affect macroscopic values
- ## each configuration will will be visited in proportion to its statistical weight (equal a priori)

The dominating configuration

- the observed conformation will be the most probable one
- properties of the system will thus be characteristic of the most probable/ dominating configuration
- this configuration can be found by looking for values of ni that lead to maximum weight

Conservation of particles and energy

- we assume the total E is constant

- must also assume that total number of particles is fixed

The boltzman distribution

The populations in the configurations of greatest weight deoend on the energy of the state