Reaction Rate Flashcards
measure of the speed of any change that occurs within an interval of time
Rate
atoms, ions, and molecules can react to form products when they collide with one another, provided that the colliding particles have enough kinetic energy
collision theory
The minimum energy that colliding particles must have in order to react
activation energy
an unstable arrangement of atoms that forms momentarily at the peak of the activation-energy barrier
activated complex
The activated complex
transition state
substance that increases the rate of a chemical reaction without itself being consumed in the reaction
catalyst
exists in the same physical state as the reaction it catalyzes
homogeneous catalyst
exists in a physical state different than that of one of the reaction it catalyzes
heterogeneous catalyst
a substance that interferes with the action of a catalyst
inhibitor
an expression for the rate of a reaction in terms of the concentration of reactants
rate law
defines how the rate is affected by the concentration of that reactant
reaction order
numerical value that relates reaction rate and concentration of reactants at a given temperature
(also known as k)
specific rate constant
the reaction is directly proportional to the concentration of only one reactant
first-order reaction
rate is proportional to the square of the concentration of one reactant
second-order reaction
reaction in which reactants are converted to products in a single step
elementary reaction
consists of two or more elementary steps
complex reaction
The series of elementary reactions or steps that take place during the course of a complex reaction.
reaction mechanism
a product of one of the steps in the reaction mechanism
intermediate
The slowest of the elementary steps in a complex reaction
rate-determining step
is one in which the conversion of reactants to products and the conversion of products to reactants occur simultaneously
reversible reaction
if a stress is applied to a system in dynamic equilibrium, the system changes in a way that relieves the stress
Le Châtelier’s principle
The ratio of product concentrations at equilibrium, with each concentration raised to a power equal to the number of moles of that substance in the balanced chemical equation
equilibrium constant
What four factors influence the rate of a chemical reaction?
Temperature, concentration, particle size, and the use of a catalyst
What does it mean if a rate constant is large?
The products form quickly
What does it mean if a rate constant is small?
The products form slowly
What does an equilibrium constant greater than one mean?
Favors the products
What does an equilibrium constant less than one mean?
Favors the reactants
