Thermodynamics an exergonic reaction放能反应 an endergonic reaction吸能反应 products reactants G G roducts reactants rogress of the reaction progress of the reaction Keg >1 △ G is negative △ G is possitive 通过热力学研究与计算,可以知道反应的终态和 始态的能量变化情况,知晓反应平衡的移动方向,判 断反应能否进行。AG=- TINk(e
Thermodynamics r eact a nts products r eact a nts products ∆ G ∆ G p r o g r ess o f t he r eactio n p r o g r ess o f t he reactio n Free energy an exer g o nic r e a ctio n 放能反 应 an end e r g o nic reactio n 吸能反应 Keq > 1 Keq < 1 ∆ G is n e g ative ∆ G is p ossitive ——通过热力学研究与计算，可以知道反应的终态和 始态的能量变化情况，知晓反应平衡的移动方向，判 断反应能否进行。 △G 0 = - RTln Keq
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）
Thermodynamics △s— Entropy change(熵变) o Entropy is the degree of disorder O AS0=(freedom of motion of products) (freedom of motion of reactants) o When Aso is negative, disorder decreases; when A so is positive, disorder increases 系统总是自动向是混乱度增加的方向变化
Thermodynamics z △S 0 —— Entropy change （熵变） z Entropy is the degree of disorder z △S 0 = (freedom of motion of products) – (freedom of motion of reactants) z When △S 0 is negative, disorder decreases; when △S 0 is positive, disorder increases. 系统总是自动向是混乱度增加的方向变化
Thermodynamics △G=△H-T∠S Standard conditions(标准状态) 1M,25℃,100kPa下 (标准状况或条件:1M,25℃,1atm=101325 △G=△H-7∠S0 当反应过程中熵变较小时,可以用焓变的情况 粗略判断反应进行的方向与平衡移动
Thermodynamics △G = △H - T△S Standard conditions (标准状态 ) ——1M, 25 ℃, 100 kPa 下 （标准状况或条件： 1M, 25 ℃, 1 atm = 101.325 kPa ） △G 0 = △H0 - T△S 0 当反应过程中熵变较小时，可以用焓变的情况 粗略判断反应进行的方向与平衡移动
Thermodynamics ●△H0 can be calculated fron/bond dissociation energy Bond Dissociation Energy (DHo (键的裂解能或离解能) defined as the amount of energy required to break a given bond to produce two radical fragments when the molecule is in gas phase at25℃ A: B A·+·B
Thermodynamics z △H0 can be calculated from bond dissociation energy z Bond Dissociation Energy (DH 0 ) （键的裂解能或离解能） —— defined as the amount of energy required to break a given bond to produce two radical fragments when the molecule is in gas phase at 25 ℃. A:B A• + •B