Energy of products in endothermic reaction

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Discussion Overview

The discussion revolves around the energy changes in endothermic reactions, specifically focusing on the enthalpy of reactants and products. Participants explore the apparent contradiction in the energy levels of reactants and products in endothermic processes, using the decomposition of hydrogen peroxide as a primary example, while also referencing combustion reactions.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant questions how the energy of products in an endothermic reaction can be less than that of the reactants, specifically citing the decomposition of hydrogen peroxide and its enthalpy values.
  • Another participant expresses confusion about the classification of decomposition as endothermic, despite the enthalpy values suggesting otherwise.
  • A different participant raises a related question about methane combustion, noting that the reactants have a lower enthalpy than the products, yet the reaction is exothermic.
  • One participant seeks clarification on what is meant by products having more or less energy than reactants, questioning whether this refers to individual measurements of chemical energies or the energy involved in bond formation and breaking.

Areas of Agreement / Disagreement

Participants express confusion and seek clarification on the concepts of enthalpy and energy changes in reactions. There is no consensus on the explanations provided, and multiple viewpoints regarding the classification of reactions remain unresolved.

Contextual Notes

Participants reference specific enthalpy values but do not provide detailed explanations of the underlying principles or assumptions related to these values. The discussion does not resolve the apparent contradictions in energy classifications.

ASidd
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How is the energy of products in endothermic reaction more than the energy of reactants
When we see the following equation of an endothermic reaction below
2H2O2--> 2H2O + O2
The 2H2O2 has an enthalpy of 2144 whereas the products have and enthalpy of 1424 Kj/mol

SO the reactants have more enthalpy than the products but the reaction is still endothermic. Why is that?

Can someone please explain this to me. Please I know this is a simple and silly question but I won't understand my energy chapter until and unless I don't know the answer of this query.
 
Chemistry news on Phys.org
Can somebody please help. I'm really desperate.
 
ASidd said:
How is the energy of products in endothermic reaction more than the energy of reactants
When we see the following equation of an endothermic reaction below
2H2O2--> 2H2O + O2
The 2H2O2 has an enthalpy of 2144 whereas the products have and enthalpy of 1424 Kj/mol

SO the reactants have more enthalpy than the products but the reaction is still endothermic. Why is that?

Can someone please explain this to me. Please I know this is a simple and silly question but I won't understand my energy chapter until and unless I don't know the answer of this query.

Why do you think the decomposition of hydrogen peroxide is endothermic?
 
I was always told that decomposition is endothermic? It's in my book.

Also in a related question concerning Methane combustion the reactants have a Delta H of 2548 whereas the products have a delta H of 3324.

Again combustion is definitely exothermic but how come the Reactants have less energy than the products?
 
There is something that I really need to understand which is what does it exactly mean when it is said that Products have less energy/ more energy than reactants?
Do they individually measure the energies of each chemical and how do they do that?

Or are the talking about the energy that is taken to make and break bonds etc.
 

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