Kinetics vocab Flashcards
Activated Complex
the arrangement of atoms found at the top of the potential
energy barrier as a reaction proceeds from reactants to products
Activation Energy
the threshold energy that must be overcome to produce a
chemical reaction
Absorption
= the collection of one substance on the surface of another
Bimolecular step
a reaction involving the collision of two molecules
Catalyst
= a substance that speeds up a reaction without being consumed
Chemical Kinetics
the area of chemistry that concerns reaction rates
Collision Model
a model based on the ideal that molecules must collide to react;
used to account for the observed characteristics of reaction rates
Differential rate law
an expression that gives the rate of a reaction as a function
of concentrations; often called the rate law
Elementary Step
a reaction whose rate law can be written from its molecularity
Enzyme
a large molecule, usually a protein, that catalyzes biological reactions
Half-life (reactant)
the time required for a reactant to reach half of its original
concentration
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.
Molecular orientation (kinetics)
orientations of molecules during collisions, some
of which can lead to reaction while other cannot
Molecularity
a number of species that elementary must collide to produce the reaction represented by an elementary step in a reaction mechanism
Order (of reactant)
the positive or negative exponent, determined by experiment,
of the reactant concentration in a rate law
rate Constant
the proportionality constant in the relationship between reaction
rate and reactant concentrations.
Rate determining step
the slowest step in a reaction mechanism, the one determining the overall rate
Rate law (differential rate law)
an expression that shows how the rate of reaction
depends on the concentration of reactants
Reaction mechanism
the series of elementary steps involved in a chemical reaction
Reaction Rate
the change in concentration of a reactant or product per unit time.
Steric Factor
the factor (always less than 1) that reflects the fraction of collisions with orientations that can produce a chemical reaction
Termolecular step
a reaction involving the simultaneous collision of three molecules
Unimolecular step
a reaction step involving only one molecule
