Activated complex
The transition state of a reaction in which old bonds are partially broken and new bonds are
partially formed. The activated complex has a higher energy than the reactants or products of the
reaction.
Activation energy (Ea)
The minimum amount of energy required for a reaction to occur.
Adiabatic process
A process that occurs without the transfer of heat to or from the system.
Alcohols
Organic compounds of the general formula R-OH.
Aldehydes
Organic compounds of the general formula R-CHO.
Alkali metals
Elements found in Group IA of the periodic table. They are highly reactive, readily losing their one
valence electron to form ionic compounds with nonmetals.
Alkaline earth metals
Elements found in Group IIA of the periodic table. Their chemistry is similar to that of the alkali
metals, except that they have two valence electrons, and thus form 2+ cations.
Alkanes
Hydrocarbons with only single bonds. The general formula for alkanes is CnH 2 n+ 2.