According to Le Chatelier's Principle, what happens to a system at equilibrium when it is subjected to a change in concentration, pressure or temperature?

The correct answer is The system shifts in the direction that opposes the change to re-establish equilibrium..

Key Points

• Le Chatelier's Principle states that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium moves to counteract the change and restore equilibrium. (Source: Chemistry LibreTexts)
• This principle applies to changes in concentration, pressure, and temperature. (Source: Royal Society of Chemistry)
• In response to a change in concentration, the system will shift to consume the added substance or produce more of the removed substance. (Source: Khan Academy)
• When pressure is altered, the equilibrium will shift towards the side with fewer or more moles of gas, depending on whether pressure is increased or decreased. (Source: BBC Bitesize)
• For changes in temperature, the system will shift towards the endothermic or exothermic direction to absorb or release heat accordingly. (Source: CK-12 Foundation)

Additional Information

• Dynamic Equilibrium:
  • It is a state in which the forward and reverse reactions occur at the same rate, resulting in no net change in the concentrations of reactants and products. (Source: Chemguide)
• Endothermic and Exothermic Reactions:
  • Endothermic reactions absorb heat, while exothermic reactions release heat. (Source: National Geographic)
  • The direction of shift in equilibrium depends on whether the reaction is endothermic or exothermic when temperature changes. (Source: ThoughtCo)
• Concentration Changes:
  • Adding more reactants or removing products will shift equilibrium towards the products side. (Source: Chem4Kids)
  • Conversely, adding more products or removing reactants will shift equilibrium towards the reactants side. (Source: Chem4Kids)
• Pressure Changes:
  • Increasing pressure favors the side with fewer moles of gas, while decreasing pressure favors the side with more moles of gas. (Source: Chemguide)
• Temperature Changes:
  • Increasing temperature favors the endothermic direction, while decreasing temperature favors the exothermic direction. (Source: Chemistry LibreTexts)