Which principle states that a system at equilibrium shifts to relieve stress?

Which principle states that a system at equilibrium shifts to relieve stress?

• A. Le Chatelier's principle
• B. Raoult's Law
• C. Law of Definite Proportions
• D. Law of Multiple Proportions

Answer: (A)

Le Chatelier's principle states that a system at equilibrium will shift in a direction that counteracts the imposed change. In a reversible reaction, forward and reverse rates balance, but when you stress the system—by changing concentrations, pressure, or temperature—it responds to partially undo that stress. For example, adding more of a reactant pushes the balance toward producing more products, while removing products pulls the balance toward forming more products to replace what was taken away. Increasing pressure tends to shift the equilibrium toward the side with fewer gas moles, and decreasing pressure does the opposite. Temperature changes affect the direction depending on whether the reaction direction absorbing heat (endothermic) or releasing heat (exothermic): heating the system pushes the equilibrium toward the endothermic direction, while cooling pushes it toward the exothermic direction. This principle helps you predict how the position of equilibrium changes without needing to know the exact rates, though the value of the equilibrium constant itself can change with temperature.

Le Chatelier's principle states that a system at equilibrium will shift in a direction that counteracts the imposed change. In a reversible reaction, forward and reverse rates balance, but when you stress the system—by changing concentrations, pressure, or temperature—it responds to partially undo that stress. For example, adding more of a reactant pushes the balance toward producing more products, while removing products pulls the balance toward forming more products to replace what was taken away. Increasing pressure tends to shift the equilibrium toward the side with fewer gas moles, and decreasing pressure does the opposite. Temperature changes affect the direction depending on whether the reaction direction absorbing heat (endothermic) or releasing heat (exothermic): heating the system pushes the equilibrium toward the endothermic direction, while cooling pushes it toward the exothermic direction. This principle helps you predict how the position of equilibrium changes without needing to know the exact rates, though the value of the equilibrium constant itself can change with temperature.