Equilibrium of reactions - which direction is favored?

Click For Summary

Discussion Overview

The discussion centers on the relationship between the equilibrium constant and the direction of chemical reactions, specifically whether the terms "products favored" and "forward reaction favored" are interchangeable. Participants explore scenarios where the equilibrium constant indicates a preference for products, yet question if the reverse reaction can still be favored under certain conditions.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Homework-related

Main Points Raised

  • Some participants propose that saying "products are favored" is equivalent to saying "the forward reaction is favored," particularly when the equilibrium constant is greater than 1.
  • Others argue that a system can have excess products and still favor the reverse reaction, especially if the calculated equilibrium constant indicates a deviation from the expected value.
  • A participant questions the meaning of "excess" products and how it relates to the speed of the forward and reverse reactions.
  • Another participant emphasizes that the equilibrium constant reflects the direction in which the reaction is favored, suggesting that if the forward reaction is favored, it should be proceeding faster.
  • There is a challenge regarding the interpretation of the equilibrium constant and its implications for reaction rates, with some asserting that the equilibrium constant indicates which direction is favored, while others contend that actual rates may differ.

Areas of Agreement / Disagreement

Participants express differing views on whether the forward reaction can be favored while the reverse reaction proceeds more quickly. The discussion remains unresolved, with multiple competing interpretations of the relationship between equilibrium constants and reaction dynamics.

Contextual Notes

Participants highlight the importance of understanding the definitions of equilibrium constants and the concept of "excess" products, which may depend on specific contexts or interpretations. There is also mention of the distinction between rate constants and actual reaction rates, which remains a point of contention.

dranseth
Messages
87
Reaction score
0

Homework Statement



Is it the same to say the products are favour and the forward reaction is favoured. Or can the reverse reaction be favoured but the products be favoured. For example, the equilibrium constant is >1 so by definition the products are favoured, but if a system has excess products and the reverse reaction is favoured, then? I am confused.
 
Physics news on Phys.org
That was one of the more confusingly phrased questions I've read.

As to your initial question, it is the same to say the products are favored or to say the forward reaction is favored. If the Equi constant is > 1, then the system doesn't have excess products (excess meaning enough to stop the reaction).
Perhaps the semantics of excess is what's confusing you?
Depending on the reaction you can have a hell-of-a-lot of products and still be favoring a forward reaction.

Hope that helps.
 
I don't understand what you mean by "excess meaning enough to stop the reaction". I'll try to give you a better example of what I am asking.

Say you are given a question and you are told that the equilibrium constant is 4. You are then told to find out if the reaction is in equilibrium, so you calculate it only to find that the equilibrium constant you calculated was 9, so you're obviously not in equilibrium and you have excess products (meaning more products than is needed to be in equilibrium). Wouldn't the reverse reaction be favoured in this case because more reactants have to be made to reach the equilibrium constant 4?
 
If your "product" is in excess, giving you the higher than expected Keq value, then the reverse reaction will proceed more quickly, to respond to the stress on the equilibrium system.
 
Thanks, so even if the reverse reaction is proceeding more quickly, the forward can be favoured as depicted by the Keq value > 1?
 
No. If the forward reaction is favored, then the forward reaction is going faster, and the products are favored - meaning more products are going to be produced.
 
That doesn't make sense with the definition then. Because in my textbook it defines that if the equilibrium constant is greater than one, then the forward reaction is favoured. Couldn't your reverse reaction be proceeding faster while having a equilibrium constant greater than one?
 
No, you cant. The equi constant tells you which direction the reaction is going ( / is going faster. Which direction the reaction is going, tells you if the products or the reactants are favored (i.e. forward = reactants favored).
 
Note that the equilibrium deals with the rate constants and not the actual rates - this aspect is very important.
 

Similar threads

Why equilibrium favours weak acid or weak base
  • · Replies 4 ·
Replies
4
Views
3K
Chemistry Relationship between chemical equilibrium and rate equilibrium
  • · Replies 2 ·
Replies
2
Views
2K
Chemistry Question about the Butler-Volmer equation in electrochemistry
  • · Replies 1 ·
Replies
1
Views
3K
Chemistry Does Combusting Different Amounts of Propane Change Final Temperature?
  • · Replies 5 ·
Replies
5
Views
3K
Chemistry How to think about increased temperature effect on water autoprotolysis equilibrium constant?
  • · Replies 4 ·
Replies
4
Views
2K
Chemistry Calculation of bond energy of oxygen gas at 0K
  • · Replies 2 ·
Replies
2
Views
2K
Chemistry Understanding the calculation of enthalpy of the formation of benzene
  • · Replies 3 ·
Replies
3
Views
3K
Chemistry Understanding chemical potential of gas in mixture versus pure gas, used in derivation of equilibrium constant
  • · Replies 1 ·
Replies
1
Views
2K
Auto Ionization of Water: Understanding the Equilibrium and Heat Transfer
  • · Replies 7 ·
Replies
7
Views
3K
How Does Increased Pressure Affect Chemical Equilibrium in the Reaction A⇔2B?
  • · Replies 5 ·
Replies
5
Views
2K