Chapter 12 - Thermodynamics

## 12.1 Spontaneous Processes

Spontaneous Process: process that proceeds without any ongoing intervention, self-sustaining once initiated; does not necessarily mean a fast or exothermic reaction

Non-spontaneous Process: cannot happen on its own

## 12.2 Entropy and the Second Law of Thermodynamics

First law of Thermodynamics: energy cannot be created or destroyed - cannot do more work than allowed by available energy

Second law of Thermodynamics: not all energy released by a spontaneous reaction is available to do useful work

* energy unavailable to do useful work spreads out and becomes less concentrated over time

Entropy: measure of energy dispersion of a system; always increases during a spontaneous process

Accessible Microstates: probable number of arrangements of particles in a system at a given temperature

Third Law of Thermodynamics: a perfect crystalline solid has zero entropy at a temperature of absolute zero

## 12.3 Absolute Entropy and Molecular Structure

Standard Molar Entropy (S**°**): entropy of one mole of a substance in its standard state

* linked to masses and molecular structures (rotational motion and rigidity)

Entropies of States: S*solid*