Mechanism
Definition
In chemistry, mechanism refers to step-by-step sequence of elementary reactions by which an overall chemical change occurs.
Analogy
Imagine building a LEGO set - each individual step and piece (elementary reaction) is necessary to complete the final model (overall chemical change).
Related terms
Rate-Determining Step: The slowest step in a reaction mechanism that determines the overall rate of the reaction.
Catalyst: A substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change.
Intermediate: A substance formed during a middle step of a chemical reaction between reactants and the desired product.
"Mechanism" appears in:
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Practice Questions (2)
- The reaction described [O3(g) + O(g) → 2O2(g)] is the decomposition of O3. With an addition of NO, the reaction proceeds in two elementary steps and a mechanism is shown: [Step 1: O3 + NO → NO2 + O2 (slow)] [Step 2: NO2 + O → NO + O2 (fast)]. Which is the rate law?
- When you _______ the elementary steps of a mechanism, an overall balanced chemical equation is given.
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