Understanding Equilibrium Constants 0 & 1

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Discussion Overview

The discussion revolves around the significance of equilibrium constants equal to 0 and 1 in chemical reactions. Participants explore the implications of these values on the concentrations of reactants and products, as well as the nature of the reactions involved.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant asks for clarification on what equilibrium constants of 0 and 1 signify regarding reactants and products.
  • Another participant suggests writing a reaction equation and its equilibrium constant expression to analyze when the constants can equal 0 or 1 based on concentrations.
  • A participant explains that Kc = 1 indicates equal concentrations of products and reactants, while Kc = 0 implies that at least one product concentration is zero.
  • Questions are raised about the implications of Kc = 0, including whether the enthalpy change is zero, if no reaction occurs, or if the activation energy is zero.
  • Discussion includes the idea that if one product's concentration is zero, it suggests no reaction has taken place, leading to a clarification on the relationship between reactants and products.
  • Another participant notes that Kc = 1 indicates dynamic equilibrium, where half of the reactants have been converted into products.
  • Further analysis is encouraged regarding the meanings of Kc values greater than or less than 1, with a note that Kc = 1 is a border case without special significance.

Areas of Agreement / Disagreement

Participants express varying interpretations of the implications of equilibrium constants of 0 and 1, with no consensus reached on the broader significance of these values in terms of reaction dynamics.

Contextual Notes

Some assumptions regarding the nature of reactions and the definitions of equilibrium constants are not explicitly stated, which may affect the interpretations presented.

ycn
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Hi, can someone help me on the following question.

Equilibrium constant=0

Equilibrium constant=1

What are the significance of these 2 values? As in, what is happening to the reactants as well as the products in this 2 instances? Thank you!
 
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Write any reaction equation (even as simple as A <-> B), write expression for its equilibrium constant. Then it is simple math - think when equilibrium constant can equal 0 and when it can can equal 1, think in terms of values of concentrations of products and reactants.
 
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But what do the numbers means?

Eg. a + b \Updownarrow c + d

Kc = [c][d]/[a]

Kc = 1 will mean [c][d] = [a]

Kc = 0 will mean either [c] is zero or [d] is zero

1. Is the enthaply change for the reaction zero?
2. Is there no reaction?
3. Is the activation energy zero?
 
Let's start with the second case. If you start with a and b - what does it mean if c or d is zero? Think about the reaction stichiometry. If c is zero - what about d? How did a and b changed?
 
That means the other product should have zero concentration. Which also means no reaction would have taken place. Oh okok, thanks a lot, really!

Then in the case for Kc = 1, amount of reactant is equal to the product. That means half of the reactants have been converted into the product, and the reaction has just reached dynamic equilibrium. So can i say it's just a normal equilibrium reaction. Thanks
 
ycn said:
So can i say it's just a normal equilibrium reaction.

Sure you can, but it won't hurt to analyse it a little bit further. Think what it does mean when Kc > 1 or Kc < 1. Where the equilibrium lies - on the left, on the right? Kc = 1 doesn't have any special meaning, but it happens to be a border case.



 
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