Learn more with dummies

Enter your email to join our mailing list for FREE content right to your inbox. Easy!

Tackling Thermodynamics Problems

By John T. Moore

Part of Chemistry II For Dummies Cheat Sheet

The Gibbs Free Energy is the best indicator about whether a reaction will be spontaneous or nonspontaneous. You’ll need to know this as you study Chemistry II. It has the form:


In this equation ΔG° is the Gibbs Free Energy of a reaction under standard conditions of 1 atm (or 1 bar) for gases and 1 M for solutions at 25°C; ΔH° is the enthalpy of the reaction under standard conditions; T is the Kelvin temperature; and ΔS° is the entropy of the reaction under standard conditions.

A spontaneous process has °G < 0. A nonspontaneous process has ΔG > 0. When °G = 0, the process is at equilibrium.