18.3 Gibbs Free Energy and the Relationship between Delta G, Delta H, & Delta S | General Chemistry

Chad continues the chapter on Thermodynamics with an introduction to Gibbs Free Energy. Simply put, Gibbs Free Energy is the energy available to do work. For a spontaneous reaction, the change in Gibbs Free Energy (Delta G) is negative. For a nonspontaneous process, the change in Gibbs Free Energy (Delta G) is positive. And for a reaction that has reach equilibrium, the change in Gibbs Free Energy (Delta G) is equal to zero. Mathematically, Delta G is defined in terms of the enthalpy and entropy changes as follows: Delta G = Delta H - T(Delta S) A reaction for which Delta H is negative and Delta S is positive will be spontaneous at all temperatures. A reaction for which Delta H is positive and Delta S is negative will be nonspontaneous at all temperatures (or the reverse reaction will be spontaneous at all temperatures). A reaction for which Delta H is negative and Delta S is negative will be spontaneous at low temperatures. A reaction for which Delta H is positive and Delta S is positive will be spontaneous at high temperatures. I've embedded this playlist as a course on my website with all the lessons organized by chapter in a collapsible menu and much of the content from the study guide included on the page. Check this lesson out at https://www.chadsprep.com/chads-general-chemistry-videos/gibbs-free-energy/ If you want all my study guides, quizzes, final exam reviews, and practice exams, check out my General Chemistry Master Course at https://www.chadsprep.com/genchem-youtube 00:00 Lesson Introduction 00:24 Introduction to Gibbs Free Energy 04:13 Derivation of Gibbs Free Energy 09:57 Delta G = Delta H - T(Delta S) 14:25 Negative Delta H, Positive Delta S 15:51 Positive Delta H, Negative Delta S 17:11 Positive Delta H, Positive Delta S 22:16 Negative Delta H, Negative Delta S 26:25 Delta H, Delta S, and Temperature of Phase Changes https://www.chadsprep.com/