Elementary Steps and Rate-Determining Steps
This page elaborates on elementary steps and their corresponding rate laws. It provides a table showing various elementary steps and their rate expressions, ranging from unimolecular to termolecular reactions.
The concept of rate-determining steps is introduced, explaining that it is the slowest step in a reaction mechanism and determines the overall rate of the reaction.
Highlight: For a mechanism to be valid, the sum of elementary steps must give the overall balanced equation for the reaction, and the experimental rate law must agree with the rate-determining step.
An example of a valid mechanism is provided for the reaction NO₂ + CO → NO + CO₂, demonstrating how the rate law is determined by the slow, rate-determining step.
Example: The page presents a problem asking to identify the rate-determining step in the reaction 2H₂ + 2NO → N₂ + 2H₂O, given the rate law R = kNO²H2.