Enthalpy

• To do a reaction, a system needs to break some bonds and form new bonds
• Break all of the bonds. Breaking bonds require energy (high heat states called "transition phrase")
• Form new bonds
• End up with product — either cause negative pre-post reaction potential energy difference (extothermic — release heat) or positive pre-post reaction potential energy (endothermic — take in heat)

\definition["The heat difference after a reaction is equal to the heat needed to break bonds and the head used to form bonds. Both values could be negative."]{Enthalpy Equation}{\(\Delta H_{rxn} = \sum{\Delta H_{breaking}} + \sum{\Delta H_{Forming}}\)} With a positive delta H, you have an endothemic reaction. With an negative delta H, you have an extothermic reaction. Extothermic reactions are favorable => they give out energy instead of needing it