An equilibrium shift occurs when the position of a chemical equilibrium changes in response to some change in conditions, such as concentration, pressure, or temperature. It’s basically the system adjusting to counteract the change, according to Le Chatelier’s Principle.
Key points:
- Forward shift: If the reaction produces more products to counter a change, the equilibrium shifts to the right.
- Backward shift: If the reaction produces more reactants, the equilibrium shifts to the left.
- Causes of shift:
- Concentration: Adding or removing reactants/products.
- Pressure: Changing the pressure (mainly affects gaseous reactions).
- Temperature: Increasing or decreasing temperature (affects exothermic and endothermic reactions differently).
- Catalysts: Do not cause an equilibrium shift; they only help the system reach equilibrium faster.
Think of it like a balance scale: if you put extra weight on one side, the system “tips” to restore balance—this is the equilibrium shifting.