BASIC PRINCIPLES

Definitions

• Bimolecular Reaction - A reaction which involves two molecules (or atoms) in the elementary step.
• Elementary Reaction - A reaction which takes place in a single step on the molecular level. An Elementary Reaction may also be defined as one in which the reaction order of each species is identical with the stoichiometric coefficient of that species for the reaction as written.
• Heterogeneous Reaction - A reaction which involves more than one phase; the reaction usually occurring at or very near the interface between the phases.
• Homogeneous Reaction - A reaction which involves only one phase.
• Molecularity - The number of molecules involved in an elementary step.
• Stoichiometric Reaction - The overall chemical reaction indicating the stoichiometric relationship between reactants and products.
• Termolecular Reaction - A reaction which involves three molecules (or atoms) in the elementary step.
• Unimolecular Reaction - A reaction which involves one molecule (or atom) in the elementary step.

Review Question

The reaction 2NO + O₂ → 2NO₂ is an example of a

Unimolecular Reaction

Bimolecular Reaction

Termolecular Reaction