CH353 - Physical Chemistry I
Spring 2013, Unique 52575

Lecture Summary, 6 February 2013

Molar entropy:  Today we looked at patterns for the magnitude of molar entropy for similar compounds at the standard state.  We made a few conclusions:

  1) Molar entropy increases with FW
  2) Molar entropy increases with additional phase transformations.
  3) Molar entropy increases with conformational degrees of freedom from molecular structure.

Microstates:  All of this implies that there is a molecular mechanism for entropy.  Today we quantified this by defining microstates: experimentally indistinguishable configurations that all lead to a single experimentally distinguishable outcome.  The more microstates available to a system, the higher its entropy.  A system will move spontaneously in the direction of increasing microstates.