Can Calorimeters Measure Enthalpy Variation of Fast Reactions?

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The discussion centers around the limitations of calorimetry in measuring enthalpy changes for various types of reactions, particularly fast reactions. It highlights that calorimeters struggle with fast reactions due to the rapid release or absorption of heat, which can lead to inaccuracies in measurement. While some participants suggest that methods exist to delay reactions, the consensus is that the speed of heat flow in fast reactions poses a significant challenge. Additionally, the issue of very slow reactions is noted, as they require impractically long times to reach equilibrium, making calorimetry less feasible. Overall, the conversation emphasizes the complexities involved in accurately measuring enthalpy changes across different reaction rates.
Sonim
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Enthalpy , Calorimeter and Hess Law Question Related
First of all this is a question that I had while reading some concepts of my book, so this isn't a homework question. I have started reading the thermochemistry chapter of my book, and it shows the story of Hess' Law and says that it was created is because a calorimeter can't be used to measure the enthalpy variation of too slow reactions, explosive reactions, fast reaction and multi-step reactions. Why can't it be used to calculate the enthalpy variation of fast reactions ?
 
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What are your thoughts on this?
 
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Likes berkeman
Actually, I think the opposite. There are ways to delay reactions, so this shouldn't be a problem. Maybe it lies on the fact that fast reactions releases/absorbs heat too fast, which results in the increase of heat flow. However, it shouldn't be a problem too, because the termometer in the calorimeter would release/absorb more heat in less time as well. Have you got any idea?
 
I agree with you on the fast reactions. However, on very slow reactions, no one has the time to wait days or weeks or years for the reaction to reach equilibrium. But, otherwise, like you, I don't see major problems.
 
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