Definition

Noun: A principle in chemistry stating that if a change in condition (such as concentration, temperature, or pressure) is applied to a system in dynamic equilibrium, the system will shift in a direction that tends to reduce or counteract the effect of that change, establishing a new equilibrium.

Usage

This term is used specifically in the context of chemical equilibrium and physical processes. It is a predictive rule for determining the direction of the shift in equilibrium when a system is disturbed.

Examples

• According to Le Chatelier's principle, increasing the pressure on a gas reaction will cause the equilibrium to shift toward the side with fewer moles of gas.
• When a reactant is added to a system at equilibrium, Le Chatelier's principle predicts the reaction will proceed in the forward direction to consume some of the added substance.
• Le Chatelier's principle explains why the solubility of a gas decreases in a solution when the temperature is raised.

Advanced Usage

• Qualitative Predictions: The principle provides qualitative, not quantitative, predictions. It tells you the of the shift (left or right, forward or reverse) but not the or new equilibrium concentrations.
• Common Stresses: It is applied to stresses including changes in concentration of reactants or products, changes in total pressure or volume (for gaseous systems), and changes in temperature.

Variants and Related Words

• Le Chatelier's Law: An alternative name for the same principle.
• Equilibrium Constant (K): A quantitative measure of the position of equilibrium, which remains constant at a given temperature despite changes in concentration or pressure, in accordance with Le Chatelier's principle.
• Equilibrium Shift: The movement of a system from one equilibrium state to another, which is what Le Chatelier's principle predicts.

Synonyms

• Equilibrium Law (in this specific chemical context)
• The Law of Mobile Equilibrium

Related Concepts

• Chemical Equilibrium: The state to which Le Chatelier's principle applies.
• Reaction Quotient (Q): A value compared to the equilibrium constant (K) to predict the direction a system must shift to reach equilibrium, providing a mathematical framework consistent with Le Chatelier's principle.

Noun

1. the principle that if any change is imposed on a system that is in equilibrium then the system tends to adjust to a new equilibrium counteracting the change