Thermochemistry

Thermochemistry deals with the enthalpy changes in chemical reactions.

The subsections that follow build this idea up systematically: the enthalpy of a chemical reaction $\Delta_r H$ — the difference between the sum of enthalpies of products and that of reactants (section 4.10.1), exothermic and endothermic reactions (4.10.2), the standard state and standard enthalpies of physical and chemical changes, thermochemical equations and the rules for writing them, standard enthalpies of formation and combustion, bond enthalpies, and Hess's law of con …