Le Chatelier's Principle
This situation is governed by Le Chatelier's Principle. It states that if a change of condition is applied to a system in equilibrium, the system will shift in a direction that relieves the stress. In this case, adding more of a reactant or product is the stress.
Shifting the Equilibrium
* Adding more reactant: The equilibrium will shift to the right, favoring the forward reaction to consume the added reactant and produce more products.
* Adding more product: The equilibrium will shift to the left, favoring the reverse reaction to consume the added product and produce more reactants.
Important Notes:
* The equilibrium constant (K) remains the same: The equilibrium constant, which expresses the ratio of products to reactants at equilibrium, does not change when you add more of a compound. The system will simply shift to maintain that specific ratio.
* The extent of the shift depends on the reaction: Some reactions are more sensitive to changes in concentration than others. The magnitude of the shift will depend on the equilibrium constant (K) and the relative amounts of reactants and products present.
Example
Consider the following reversible reaction:
```
N2(g) + 3H2(g) ⇌ 2NH3(g)
```
If we add more nitrogen (N2) to this system at equilibrium, the equilibrium will shift to the right, favoring the formation of ammonia (NH3).
Summary
Adding more of one compound to a system at equilibrium will cause the system to shift in a direction that relieves the stress. This means the reaction will favor the production of more products if a reactant is added or the production of more reactants if a product is added.
