Definition

Noun: - Le Chatelier-Braun principle: A fundamental principle in physical chemistry which states that if a system in dynamic equilibrium is subjected to a change in conditions (such as concentration, pressure, or temperature), the equilibrium will shift in a direction that tends to counteract or reduce the effect of that change, thereby establishing a new equilibrium.

Usage Examples

• Noun:
  • When pressure is increased on a gaseous reaction at equilibrium, the system shifts according to the Le Chatelier-Braun principle to favor the side with fewer moles of gas.
  • The Le Chatelier-Braun principle predicts that adding more reactant to an equilibrium mixture will cause the reaction to produce more product.

Advanced Usage

• "Applying the Le Chatelier-Braun principle": Used to describe the analytical process of predicting how a system at equilibrium will respond to an external stress.
  • By applying the Le Chatelier-Braun principle, we can understand why the yield of ammonia increases at higher pressures in the Haber process.

Variants and Related Words

• Le Chatelier's principle (n): A more common name for the same principle, often used interchangeably.
  • Le Chatelier's principle is a cornerstone concept for students of chemistry.
• Equilibrium (n): A state in which opposing forces or influences are balanced.
• Chemical equilibrium (n): The state in a reversible chemical reaction where the rates of the forward and reverse reactions are equal.

Synonyms

• Le Chatelier's law: A synonymous term for the same principle.
• The equilibrium law: A more general term that can refer to this principle.

Related Phrases

• Shift the equilibrium: To cause a change in the position of an equilibrium, as predicted by the principle.
  • Adding a catalyst speeds up the reaction but does not shift the equilibrium.
• Stress the system: To apply a change (in concentration, pressure, temperature) to a system at equilibrium.
  • Heating the mixture stresses the system, causing the equilibrium to shift.

Related Concepts

• Common-ion effect: An application of the principle where adding an ion common to an equilibrium suppresses the ionization of a weak electrolyte.
• Vapor-liquid equilibrium: A type of phase equilibrium where the principle can be applied to predict changes.

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