Chemical Equilibrium: A Dynamic Balance?

📌 CONCEPT: Chemical equilibrium is a dynamic balance where the rates of forward and reverse reactions are equal, resulting in no net change in concentrations of reactants and products over time.

📐 RULE / FORMULA: According to Le Chatelier's principle, when a change in concentration, temperature, or pressure is applied to a system at equilibrium, the equilibrium will shift in a direction that tends to counteract the effect of the change.

💡 WORKED EXAMPLE: Let's consider the reaction A ⇌ B at 298 K and 1 atm. When the total pressure is doubled to 2 atm, the equilibrium will shift to the side with fewer moles of gas, i.e., the side with B. This is because an increase in pressure favors the side with fewer moles of gas. As a result, the concentration of B will increase, and the concentration of A will decrease.

⚠️ COMMON MISTAKE: Students often mistake Le Chatelier's principle as a rule that always favors the formation of products, but it's actually a principle that describes how the equilibrium will shift in response to a change in the system.