# 23: The Ensemble Treatment

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• 23.1: Ensembles of N-molecule Systems
Imagine collecting n N-molecule, constant-volume, constant-temperature systems. An aggregate of many multi-molecule systems is called an ensemble. Just as we assume that no forces act among the non-interacting molecules we consider earlier, we assume that no forces act among the systems of the ensemble. However, as we emphasize above, our model for the systems of an ensemble recognizes that intermolecular forces among the molecules of an individual system can be important
• 23.2: The Ensemble Entropy and the Value of ß
• 23.3: The Thermodynamic Functions of the N-molecule System
We can find the other thermodynamic functions for the N -molecule system from the equations for Z and P^i by the arguments we used previously.

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