activated complex
a transitional structure that results from an effective collision and that persists while old bonds are breaking and new bonds are forming
activation energy
Energy needed to get a reaction started
catalysis
the acceleration of a chemical reaction by a catalyst
collision theory
states that atoms, ions, and molecules must collide in order to react
complex reaction
a chemical reaction that consists of two or more elementary steps
differential rate law
expression that gives the rate of a reaction as a function of concentrations; often called rate law
first order
s-1
half-life
the time required for a reactant to reach half of its original concentration
heterogeneous catalyst
A catalyst that is in a different phase from that of the reactant substances.
homogeneous catalyst
a catalyst that is in the same phase as all the reactants and products in a reaction system
Initial reaction rate
Rate of reaction at the beginning of the reaction.
instantaneous rate
The rate of decomposition at a specific time, calculated from the rate law, the specific rate constant, and the concentrations of all the reactants.
integrated rate law
an expression that shows the concentration of a reactant as a function of time
intermediate
a species that is neither a reactant nor a product but that is formed and consumed in the reaction sequence
method of initial rates
determines reaction order by comparing the initial rates of a reaction carried out with varying reactant concentrations
rate determining step
the slowest step in a reaction mechanism, the one determining the overall rate
rate law
an expression relating the rate of a reaction to the concentration of the reactants
reaction mechanism
the series of elementary steps involved in a chemical reaction
relative reaction rate
The change in concentration of a reactant per unit time
second order
1/[A]t = kt + 1/[A]0
specific rate constant
a proportionality constant relating the concentrations of reactants to the rate of the reaction
zero order
m/s or rate=k