The difference in energy between the reactants and the transition state
that is the energy barrier
the reactants must overcome to achieve a chemical reaction.
A substance that lowers the activation energy for a chemical reaction
without being chemically
altered by the reaction.
A reaction that represents a single collision or intramolecular step in a
A catalyst that is in the same phase as the reactants.
A species that is both produced and consumed in a chemical reaction. As
such, it does not appear in
the overall reaction but is proposed to be produced in one elementary
step and consumed in
The study of the rate and mechanism of chemical reactions.
The series of elementary steps that combine to produce the path molecules
take from reactant(s) to
product(s) in a chemical reaction.
In the rate law of a reaction, the power to which the concentration of a
reagent is raised. Or, the sum of the powers on the concentration terms in the
The speed of a reaction measured in amount or reagent consumed or product
produced per unit time.
The proportionality constant in the rate law expression. This factor
is a measure of the intrinsic
reactivity of the reaction but is not constant with respect to temperature.
An expression of the dependence of the rate of a reaction on the
concentrations of reactants.
Rate Limiting Step
The slowest elementary step in a mechanism. The rate of the reaction
equal the rate of the
slowest step because the reaction can go no faster than its slowest step.
Reaction Coordinate Diagram
A plot of free energy versus the reaction coordinate for a reaction that
provides a pictorial
representation of the lowest energy path from reactants to products.
The assumption that the rate of formation and consumption of a highly
reactive intermediate are equal
so that the change in intermediate concentration with respect to time is
approximated to be zero.
The species with the highest energy between reactants and products on a
diagram, it is a short-lived species that represents a combination of
product-like and reactant-like