CONSIDER THE FOLLOWING MECHANISM : O₃ → O₂ ₊ O (fast ) O₃ + O → 2O₃ (slow) what is the overall balanced chemical equation? identify any intermediates within the mechanism? what is the molecularity with respect to each reaction?
Answers
Answer:
Explanation:
Key Points
Elementary reactions sum to the overall reaction equation.
Rate laws for elementary steps are derived from the molecularity of each step.
Reaction mechanisms can agree with experimental data, but can never be proven for certain.
Key Terms
unimolecular: Involving a single molecule.
molecularity: Referring to the number of individual molecules involved in an elementary step of a reaction mechanism.
bimolecular: Involving two molecules.
elementary step: A single transformation in an overall reaction mechanism; can be unimolecular, bimolecular, or termolecular.
Reaction Mechanisms
Every chemical reaction proceeds according to a reaction mechanism, which is a step-by-step description of what occurs during a reaction on the molecular level. Each step of the mechanism is known as an elementary process, which describes a single moment during a reaction in which molecules break and/or form new bonds. It is important to keep in mind that every reaction mechanism is simply a proposed version of what might be occurring at the molecular level; even if a mechanism agrees with experimental results, it is impossible to prove a reaction mechanism for certain. That being said, there are two strict requirements that must be fulfilled for a reaction mechanism to be valid. They are:
The sum of each elementary step in a reaction mechanism must yield the overall reaction equation.
The rate law of the rate-determining step must agree with the experimentally determined rate law.
The rate-determining step is the slowest step in a reaction mechanism. Because it is the slowest, it determines the rate of the overall reaction. This will be explored later in more detail.
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Change in concentration of chemicals over time: A plot of time versus concentration for two species in chemical equilibrium.
Elementary Reactions and Their Rate Laws
Elementary reactions are classified in terms of their molecularity; that is, by how many molecules are involved in the given step. There are three possible molecularites: