Thermodynamics △H— Enthalpy change(焓变) o Enthalpy is the heat given off or the heat consumed during the course of a reaction AH0=(energy of the bonds being broken (energy of the bonds being formed) o When AHO is negative, the reaction releases heat and is exothermic(放热的).When△H0 is positive, the reaction absorbs heat and is enderthermic(吸热的)Thermodynamics z △H 0 —— Enthalpy change （焓变） z Enthalpy is the heat given off or the heat consumed during the course of a reaction. z △H 0 = (energy of the bonds being broken) – (energy of the bonds being formed) z When △H 0 is negative, the reaction releases heat and is exothermic（放热的）. When △H 0 is positive, the reaction absorbs heat and is enderthermic（吸热的）