Chemistry / Unit 9 Chem 1638 short lesson, about 20 seconds
Rate Laws Come From Experiment, Not Stoichiometric Coefficients
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The idea
A rate law's reaction orders are determined by experiment, never predicted from an equation's stoichiometric coefficients.
In practice
For NO2 + CO → NO + CO2, the measured rate law below 225 °C is second order in NO2 and zero order in CO, though coefficients equal one.
Where people slip
Matching an order to its coefficient is coincidence for an overall equation — only experiment establishes it.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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