Chemical Equilibrium Question

In summary, equilibrium is a dynamic state where the rate of the reverse reaction is equal to the rate of the forward reaction. This means that while there are still interactions happening, the concentrations of products and reactants will not change. This is because reactions are constantly occurring at a molecular level, with particles colliding and forming bonds. Equilibrium does not mean that reactions stop completely, but rather that they are happening at equal rates.
  • #1
Hey guys,

I have a question regarding the process by which a reaction returns to equilibrium.

If a reaction's reaction quotient is greater than its equilibrium constant, it will shift towards the reactants side of the equation to return to equilibrium. How exactly does this happen? Does the forward reaction stop, or does the rate of the reverse reaction increase so reactants are being produced quicker than products? Is there ever a point where products or reactants are not being produced at all?
 
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  • #2
Equilibrium does not mean things stop moving or reacting or what not. You have to look at chemical processes as particles which are constantly vibrating, moving, deforming, colliding etc. It is pretty much chaos. When you see an illustration or video of two molecules neatly coming together and forming bonds or what-have-you, you must understand that it is only a model used to describe an interaction. In reality, those two molecules may have collided a zillion times without the proper orientation or energy to form bonds and on the zillionth and one collision they have enough energy and the proper orientation to actually form energetically favorable bonds. Taking this view point makes it pretty intuitive that rates of reactions rely heavily on concentrations of reactants.

Now as far as equilibrium goes, it means that the rate of the reverse reaction exactly equals the rate of the forward reaction. There are still interactions happening, with bonds breaking and forming, its just that if you measure concentrations of products and reactants they will have not net change. Weak acids for instance don't just dissociate to a specific amount and just sit around in a predictable ratio. Its more like the acidic protons are zooming throughout the whole system constantly associating and dissociating with anything that can accommodate them. Its just that the net result is one where there is no more change in concentration of acid and conjugate base. But if you follow on molecule around, hypothetically, it is constantly being protonated and deprotonated.
 
  • #3
To add to Yanick's answer - this is so called kinematic approach to equilibrium, and equilibrium is dynamic - there are both forward and forward reaction taking place, but their speeds are equal.
 

1. What is chemical equilibrium?

Chemical equilibrium is a state in a chemical reaction where the concentrations of reactants and products remain constant over time. This means that the forward and reverse reactions are occurring at the same rate, resulting in no net change in the concentrations of the reactants and products.

2. How is chemical equilibrium achieved?

Chemical equilibrium is achieved when the rate of the forward reaction is equal to the rate of the reverse reaction. This can be achieved by altering the temperature, pressure, or concentration of the reactants and products in the system.

3. What does the equilibrium constant (K) represent?

The equilibrium constant, or K, represents the ratio of the concentrations of products to reactants at equilibrium. It is a measure of the extent to which a reaction has reached equilibrium and is dependent on the temperature of the reaction.

4. How does Le Chatelier's principle apply to chemical equilibrium?

Le Chatelier's principle states that when a system at equilibrium is subjected to a stress, the system will shift in a direction that minimizes the effect of the stress. This means that if the concentration, temperature, or pressure of the reactants or products is changed, the equilibrium will shift to counteract this change.

5. What factors can affect chemical equilibrium?

The factors that can affect chemical equilibrium include temperature, pressure, and concentration. Changes in these factors can cause a shift in the equilibrium, resulting in a change in the concentrations of reactants and products. Catalysts can also affect equilibrium by altering the rate of the forward and reverse reactions.

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