18 terms

# Chapter 17

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Activated Complex
A short-lived, unstable arrangement of atoms that may break apart and re-form the reactants or may form products; also sometimes referred to as the transition state.
Activation Energy
The minimum amount of energy required by reacting particles in order to form the activated complex and lead to a reaction.
Catalyst
A substance that increases the rate of a chemical reaction by lowering activation energies but is not itself consumed in the reaction.
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.
Heterogeneous Catalyst
A catalyst that exists in a different physical state than the reaction it catalyzes.
Homogeneous Catalyst
A catalyst that exists in the same physical state as the reaction it catalyzes.
Inhibitor
A substance that slows down the reaction rate of a chemical reaction or prevents a reaction from happening.
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.
Intermediate
A substance produced in one elementary of a complex reaction and consumed in a subsequent elementary step.
Method of the initial rates
Determines the reaction order by comparing the initial rates of a reaction carried out with varying reactant concentrations.
rate-determining step
The slowest elementary in a complex reaction; limits the instantaneous rate of the overall reaction.
rate law
The matematical relationship between the rate of a chemical reaction at a given temperature and the concentrations of the reactants.
reaction mechanism
The complete sequence of elementary steps that make up a complex reaction.
reaction order
For a reactant, describes how the rate is affected by the concentration of that reactant.
reaction rate
The change in concentration of a reactant or product per unit time, generally calculated and expressed in moles per liter per second.
specific rate constant
A numerical value that relates reaction rate and concentration of reactant at a specific temperature.
transition state
Term used to describe an activated complex because the activated complex is as likely to form reactants as it is to form products.