Direction of equilibrium if you remove heat from exothermic reaction

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Discussion Overview

The discussion centers around the effects of heat removal on the equilibrium of an exothermic reaction, specifically in the context of Le Chatelier's principle. Participants explore the implications of this principle in relation to temperature changes and equilibrium shifts in chemical reactions.

Discussion Character

  • Exploratory
  • Debate/contested
  • Homework-related

Main Points Raised

  • Some participants inquire about the specifics of Le Chatelier's principle and its application to equilibrium shifts when heat is removed from an exothermic reaction.
  • One participant suggests that removing heat from a system would cause the equilibrium to shift towards the products, treating heat as a product of the reaction.
  • Another participant presents an example of freezing water as an exothermic reaction, noting that removing heat results in more ice formation without changing the equilibrium constant.
  • A participant raises a question about the vagueness of the term "removing heat" and its implications for equilibrium shifts.
  • One participant shares a homework question regarding the combustion of ethanol and expresses their reasoning that removing heat would shift the equilibrium to the right.
  • Another participant critiques the choice of the combustion of ethanol as a system reaching equilibrium, questioning the educational value of such examples.
  • A later reply distinguishes between two methods of removing heat (cooling vs. compressing) and suggests that the equilibrium shift could depend on the method used.
  • One participant asserts that the equilibrium would shift to the right when heat is removed, expressing uncertainty about their reasoning but affirming their conclusion.

Areas of Agreement / Disagreement

Participants express differing views on the effects of heat removal on equilibrium, with some supporting the idea that it shifts to the right and others suggesting that the outcome may depend on the method of heat removal. The discussion remains unresolved regarding the definitive impact of heat removal on equilibrium shifts.

Contextual Notes

Participants reference specific examples and scenarios, but there are limitations in the clarity of definitions and assumptions regarding the treatment of heat in chemical reactions. The discussion does not resolve the complexities involved in these scenarios.

lonely_nucleus
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If you remove heat from an exothermic reaction will the equilibrium shift to the products or to the reactants according to le chatelier's principle
 
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Can you state Le Chatelier's principle?
 
Borek said:
Can you state Le Chatelier's principle?
With my own words I can state it as a law that predicts the direction of an equilibrium change(to the left means reactants, to the right means products) caused by changes such as pressure, changes, or amount of reactants/products added to the system.

From wiki here is the law "Le Châtelier's principle, also called Chatelier's principle or "The Equilibrium Law", can be used to predict the effect of a change in conditions on a chemical equilibrium"
 
lonely_nucleus said:
I can state it as a law that predicts the direction of an equilibrium change(to the left means reactants, to the right means products) caused by changes such as pressure, changes, or amount of reactants/products added to the system.

So you have stated what it is, I asked what it says.
 
Borek said:
So you have stated what it is, I asked what it says.
It says that you can predict the direction of equilibrium due to a change in the system, equilibrium will always want to level out or be balanced. For example if you remove some products from a reaction then the products will be producing less reactants and the equilibrium will shift to the right(product side). My source of information did not go into detail about explaining what it says.
 
What is you treat heat as a product?
 
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What do you mean with "removing heat"?
Your question is very vague.
Consider the following example: Freezing of water is an exothermic reaction. At 0 degrees C water and ice are in equilibrium. You can remove heat from the system and more product (ice) will form. However, the equilibrium constant will not change as the concentrations of reactants and products don't change. There is always pure water and pure ice.
 
Last edited:
Yes, but he wasn't asking about the effect of changing the temperature, was he?
 
  • #10
This is similar to a question I have on homework I did not want to say the exact question but if it helps I will because I am not sure if my inference is correct.. Here is the actual question

"
Consider the following reaction occurring in a closed chemical system. Assume that this reaction is at equilibrium and that in general the reaction to the right is favored.

CH3CH2OH + 3O2 ---><--- 2CO2 + 3H2O ∆H = –1,235 kJ/mol
If heat is removed from the system, how will the reactions shift to reach equilibrium?"

I believe the equilibrium would shift to the right because if you treat matter as energy and energy is released by the products then removing heat is like removing matter from the products causing the equilibrium to shift to the right. Am I correct?
 
  • #11
Poor lad! Who asks such nonsensical questions and what are you supposed to learn from them? Burning ethanole as an example of a reaction reaching equilibrium?
 
  • #12
DrDu said:
Poor lad! Who asks such nonsensical questions and what are you supposed to learn from them? Burning ethanole as an example of a reaction reaching equilibrium?
ok?
 
  • #13
Ok, so leaving aside the strangeness of the system chosen, there are two different ways to suck heat from this system: either you cool it (at constant pressure) or you compress it (at constant temperature). In the first case your argument is correct. However in the second case, the equilibrium shifts to the left.
 
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  • #14
The correct answer is the equilibrium would shift to the right. I am not sure if I was thinking correctly to get the solution but it is correct. Thanks for the help friends.
 

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