Part One I › Division II II › Section 123 123

Chemical Reactions

Subject Outline

AGeneral considerations of chemical reactions
- 1Basic concepts involved in the study of chemical reactions: transformation, conservation of mass and energy, law of simple multiple proportions in compounds
- 2Growth of major theories concerning chemical reactions
- 3Classification and nomenclature of the principal kinds of chemical reactions
  - aAccording to the relationship involved between the starting materials and the final products
    - iDecomposition reactions
    - iiPolymerization reactions
    - iiiChain reactions
    - ivSubstitution reactions
    - vAddition and elimination reactions
    - viOxidation-reduction reactions [see F., below]
    - viiAcid-base reactions [see E., below]
  - bAccording to the energy changes involved [see B.1., below]
  - cAccording to the reaction rates or chemical kinetics involved [see also C., below]
  - dAccording to the reaction mechanism involved [see D.4., below]
BEnergy changes in chemical reactions
- 1The classification of chemical reactions according to energy changes involved: exothermic and endothermic
- 2The significance of activation energy in chemical reactions
- 3Thermodynamic relations in chemical reactions: chemical equilibrium, free energy and entropy changes
CRates of chemical reactions
- 1Factors that affect the rate or direction of chemical reactions
  - aSolvents
  - bTemperature
  - cPressure
  - dCatalysts
  - eCollisions
  - fLight
  - gIsotopic substitution
  - hMolecular structure
- 2Factors that affect the kinetic order of chemical reactions: concentration of reactants, mechanism of reaction, conditions of the reaction
- 3Factors that affect the extent of chemical reactions: equilibrium constant
- 4Complex reactions: reactions governed by more than one reaction rate
- 5Experimental methods for studying chemical kinetics
  - aMeasurement of reaction rates
  - bDetermination of the order of reactions
  - cRelaxation methods
- 6Kinetic studies as a means of elucidating reaction mechanisms
DMechanisms of chemical reactions
- 1Factors influencing the course of a reaction: reactants, transition state, solvent, catalysts, products, reaction conditions
- 2Energy changes through single-stage and multi-stage processes
- 3Factors that reveal the mechanisms of a reaction: chemical and stereochemical nature of the reactants, intermediates, and products; kinetics of the reaction
- 4Classification of reaction mechanisms based on the nature of electron pairing in the transition state, on the nature of the attacking species, on the nature of catalysis, on the number of components of the transition state
- 5Mechanisms of the principal types of reactions: nucleophilic and electrophilic substitution, addition and elimination reactions
EAcid-base reactions and equilibria
- 1General properties of acids and bases
- 2Theoretical approaches to acid-base concepts
  - aThe definition of an acid as a substance that gives rise to hydrogen ions and of a base as a substance that gives rise to hydroxyl ions in aqueous solutions
  - bThe Bronsted-Lowry concept defining an acid as a proton donor and a base as a proton acceptor
  - cThe Lewis electronic theory defining an acid as an electron acceptor and a base as an electron donor
- 3Acid-base reactions
  - aProton-transfer reactions
  - bLewis acid reactions
  - cAcid-base catalysis
- 4Quantitative aspects of acid-base equilibria
  - aEquilibria in aqueous solutions
  - bEquilibria in nonaqueous solvents
  - cEquilibria involving Lewis acids
  - dThe effect of molecular structure on acid-base equilibria
- 5The experimental study of acid-base reactions and equilibria
FOxidation-reduction reactions
- 1Major classes of oxidation-reduction reactions: oxygen atom transfer, hydrogen atom transfer, electron transfer
- 2Definitions of oxidation and reduction based on the reaction's stoichiometry
- 3Theoretical aspects of oxidation-reduction processes
  - aThe concept of oxidation state
  - bHalf reactions and the determination of redox potentials
  - cOxidation-reduction equilibria and reaction rates
  - dMechanisms of redox reactions
- 4Electrochemical reactions: chemical changes associated with the passage of an electrical current
  - aThe electrochemical process: types of reactions
  - bComplex electrochemical reactions
  - cThe Nernst and Butler- Volmer equations
- 5Oxidation-reduction reactions in biological systems
- 6Oxidation-reduction reactions in combustion and flames
GPhotochemical reactions
- 1The photochemical process
- 2Experimental methods used in the study of the photochemical process and photochemical reactions
- 3The application of photochemical processes
HChemical reactions and chemical theory in the synthesis of chemical compounds
- 1Factors that affect the choice of a specific synthetic path
- 2Factors that affect the choice of reaction conditions
- 3The separation and purification of reaction products [see 122.B.1.]