Enthalpy Standard and Hess Law

This lecture covers the concept of standard enthalpy of formation (Af H) and the application of Hess's Law in determining standard enthalpies. It explains how Af H is related to the formation of a pure substance at standard conditions and how Hess's Law can be used to calculate enthalpies for reactions. Various standard enthalpies, such as fusion, vaporization, ionization, attachment, dissociation, and lattice enthalpies, are also discussed. Through examples and exercises, students learn how to apply these concepts to calculate enthalpies of formation and reactions.