🧊thermodynamics ii review

key term - Le Chatelier's Principle

Definition

Le Chatelier's Principle states that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium shifts to counteract that change and restore a new equilibrium. This principle is crucial in understanding how systems respond to changes in concentration, pressure, and temperature, allowing for predictions about the direction of chemical reactions and phase stability.

5 Must Know Facts For Your Next Test

  1. Le Chatelier's Principle applies to changes in concentration, temperature, and pressure, predicting how a system will shift to restore balance.
  2. Increasing the concentration of reactants will shift the equilibrium toward the products to consume the added reactants.
  3. If pressure is increased in a gaseous reaction with unequal moles of gas on either side, the equilibrium will shift toward the side with fewer moles of gas.
  4. Increasing temperature shifts the equilibrium in an endothermic reaction toward products, while it shifts exothermic reactions toward reactants.
  5. The principle can be visually represented using ice-water-vapor phase diagrams, showing how changes in conditions affect phase stability.

Review Questions

  • How does Le Chatelier's Principle explain the effect of increasing reactant concentration on an equilibrium system?
    • According to Le Chatelier's Principle, when reactant concentration is increased in a system at equilibrium, the system will respond by shifting the equilibrium position toward the products. This occurs because the system attempts to counteract the change by consuming some of the added reactants, thereby restoring balance. As a result, more products are formed until a new equilibrium is established.
  • Discuss how Le Chatelier's Principle can be applied to predict the outcome of changes in temperature for both endothermic and exothermic reactions.
    • Le Chatelier's Principle indicates that for endothermic reactions, increasing temperature will shift the equilibrium toward the product side since heat is absorbed during this process. Conversely, for exothermic reactions, increasing temperature will shift equilibrium toward the reactant side because heat is released. This differentiation helps predict how reaction yields will change with temperature adjustments.
  • Evaluate how Le Chatelier's Principle interacts with chemical potential in determining phase stability under varying conditions.
    • Le Chatelier's Principle interacts with chemical potential by illustrating how shifts in equilibrium due to external changes impact phase stability. Chemical potential indicates the tendency of a substance to change its phase or state based on its environment. When conditions like pressure or temperature vary, Le Chatelier's Principle predicts how an equilibrium will adjust, influencing which phases are stable. This interplay helps understand phenomena like phase transitions and stability zones depicted in phase diagrams.