rate constants


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rate con·stants (k),

proportionality constants equal to the initial rate of a reaction divided by the concentration of the reactant(s); for example, in the reaction A → B + C, the rate of the reaction equals -d[A]/dt = k1[A]. The rate constant k1 is a unimolecular rate constant because only one molecular species is reacting and has units of reciprocal time (for example, s-1). For the reverse reaction, B + C → A, the rate equals -d[B]/dt = d[A]/dt = k2[B][C]. The rate constant k2 is a bimolecular rate constant and has units of reciprocal concentration-time (for example, M-1 s-1).
Synonym(s): velocity constants

rate con·stants

(k) (rāt kon'stănts)
Proportionality constants equal to the initial rate of a reaction divided by the concentration of the reactant(s); e.g., in the reaction A → B + C, the rate of the reaction equals -d[A]/dt = k1[A]. The rate constant k1 is a unimolecular rate constant, since there is only one molecular species reacting, and has units of reciprocal time (e.g., sec-1). For the reverse reaction, B + C → A, the rate equals -d[B]/dt = d[A]/dt = k2[B][C]. The rate constant k2 is a bimolecular rate constant and has units of reciprocal concentration-time (e.g., m-1 sec-1).
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