Preferred Label : half life;
Detailed label : half life, t1/2;
IUPAC definition : For a given reaction the half life t1/2 of a reactant is the time required for its
concentration to reach a value that is the arithmetic mean of its initial and final
(equilibrium) values. For a reactant that is entirely consumed it is the time taken
for the reactant concentration to fall to one half its initial value: The half life
of a reaction has meaning only in special cases: ol li For a first-order reaction,
the half life of the reactant may be called the half life of the reaction. /li
li For a reaction involving more than one reactant, with the concentrations of the
reactants in their stoichiometric ratios, the half life of each reactant is the same,
and may be called the half life of the reaction. /li /ol If the concentrations
of reactants are not in their stoichiometric ratios, there are different half lives
for different reactants, and one cannot speak of the half life of the reaction.;
Origin ID : H02716;
Automatic exact mappings (from CISMeF team)
- See also
For a given reaction the half life t1/2 of a reactant is the time required for its
concentration to reach a value that is the arithmetic mean of its initial and final
(equilibrium) values. For a reactant that is entirely consumed it is the time taken
for the reactant concentration to fall to one half its initial value: The half life
of a reaction has meaning only in special cases: ol li For a first-order reaction,
the half life of the reactant may be called the half life of the reaction. /li
li For a reaction involving more than one reactant, with the concentrations of the
reactants in their stoichiometric ratios, the half life of each reactant is the same,
and may be called the half life of the reaction. /li /ol If the concentrations
of reactants are not in their stoichiometric ratios, there are different half lives
for different reactants, and one cannot speak of the half life of the reaction.
