厦门大学化学化工学院：《有机化学》课程教学资源（课件讲稿，双语版）Chapter 3 An Introduction to Organic Reactions：Acids and Bases（3.8-3.15）Energy Changes

ORGANIC CHEMISTRY Chapter 3 3.8 Energy Changes Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 3 3.8 Energy Changes

ORGANIC CHEMISTRY Chapter 3 Energy and the relative Stability o kinetic energy is the energy an object has because of its motion o Potential energy is stored energy. It exists only when an attractive or repulsive force exists between objects o Chemical energy is a form of potential energy o The relative stability of a system is inversely relative potential energy o The more potential energy an object has, the less stable it is Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 3 Energy and the Relative Stability Kinetic energy is the energy an object has because of its motion. Potential energy is stored energy. It exists only when an attractive or repulsive force exists between objects. Chemical energy is a form of potential energy. The relative stability of a system is inversely relative potential energy. The more potential energy an object has, the less stable it is

ORGANIC CHEMISTRY Chapter 3 3.8A Potential Energy and covalent Bonds H+HH—H△H°=-435 kJ mol-1 H。+●H o Enthalpy relative potential energy of molecules 435 kJ mol-1 o Enthalpy change,△H° H—H Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 3 3.8A Potential Energy and Covalent Bonds H H + H H ∆H° = -435 kJ mol-1 H H + H H 435 kJ mol-1 Enthalpy — relative potential energy of molecules Enthalpy change, ∆H°

ORGANIC CHEMISTRY Chapter 3 3. 9 The Relationship Between the Equilibrium Constant and the Standard Free-Energy Change, AGo Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 3 3.9 The Relationship Between the Equilibrium Constant and the Standard Free-Energy Change, ∆G°

ORGANIC CHEMISTRY Chapter 3 o a negative value of ago is associated with reactions that favor the formation of products when equilibrium is reached ° a positive value of△ go is associated with reactions for which the formation of products at equilibrium is unfavorable Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 3 A negative value of ∆G° is associated with reactions that favor the formation of products when equilibrium is reached. A positive value of ∆G° is associated with reactions for which the formation of products at equilibrium is unfavorable

ORGANIC CHEMISTRY Chapter 3 3.10 The Acidity of Carboxylic Acids Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 3 3.10 The Acidity of Carboxylic Acids

ORGANIC CHEMISTRY Chapter 3 3. 10A An Explanation Based on Resonance effects o Molecules and ions are stabilized by resonance especially when the molecule or ion can be represented by two or more equivalent resonance structures CHa- H2O、—CH3C + hro o-H CH CH-C o-H Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 3 3.10A An Explanation Based on Resonance Effects Molecules and ions are stabilized by resonance especially when the molecule or ion can be represented by two or more equivalent resonance structures. CH3 C O O H + H2O CH3 C O O + H3O CH3 C O O H CH3 C O O

ORGANIC CHEMISTRY Chapter 3 3. 10B an Explanation bases on Inductiⅴ e effects CH2C≤0≤H CH2-CHo-o<H CH2-C<O CH2一CH2-0 Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 3 3.10B an Explanation Bases on Inductive Effects CH3 C O < O< H < CH3 CH2 O< H CH3 C O < O < CH3 CH2 O

ORGANIC CHEMISTRY Chapter 3 3.10C Inductive Effects of other groups CH2C≤0≤H Cl≤CH2-C≤0H ClCH2-C≤O Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 3 3.10C Inductive Effects of Other Groups CH3 C O < O< H < CH2 C O < O< H < Cl< CH2 C O < O < Cl<

ORGANIC CHEMISTRY Chapter 3 3.11 The effect of the solvent on Acidity Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 3 3.11 The Effect of the Solvent on Acidity