Dynamic equilibrium 2.3.1

Why is a closed system more suitable for achieving dynamic equilibrium than an open system?

It prevents the loss of reactants and products, maintaining constant concentrations. In an open system, reactants or products can escape, preventing the establishment of constant concentrations and thus a true dynamic equilibrium.

Compare the significance of constant concentration versus equal reaction rates in defining dynamic equilibrium. Which is more critical for identifying equilibrium and why?

Equal reaction rates, because they maintain the balance of reactants and products. While constant concentrations are observed at equilibrium, they are a consequence of the forward and reverse reaction rates being equal. It's the equality of rates that defines the dynamic nature of equilibrium, where reactions are continuously occurring in both directions.

Evaluate how the representation of reversible reactions (\rightleftharpoons) helps chemists predict reaction behavior. Is symbolic notation sufficient for understanding equilibrium dynamics?

No, because it doesn’t indicate reaction rates or concentrations. While the \rightleftharpoons symbol indicates that a reaction is reversible and can reach equilibrium, it does not provide quantitative information about the equilibrium position, reaction rates, or the concentrations of reactants and products at equilibrium. For a deeper understanding, information like equilibrium constants (K), initial concentrations, and kinetic data is needed.

In what ways does the energy change of a reversible reaction (exothermic vs. endothermic) influence how equilibrium responds to temperature changes? Which direction is more sensitive and why?

The endothermic direction is more sensitive because it favors heat absorption. According to Le Chatelier's Principle, an increase in temperature will shift the equilibrium in the endothermic direction (the direction that absorbs heat) to counteract the change. Conversely, a decrease in temperature will shift it in the exothermic direction (the direction that releases heat). Both directions are sensitive, but the shift favors the endothermic process when heat is added.

5. Assess the importance of macroscopic properties (e.g., color, density) in identifying equilibrium. Are they reliable indicators compared to molecular-level data?

Yes, because they reflect constant concentrations at equilibrium.

📘 Explanation: Macroscopic properties remain unchanged at equilibrium because the concentrations of reactants and products are stable. They’re useful indicators, though not as precise as molecular measurements.

6. Why does the reverse reaction rate increase over time in a reversible reaction? Evaluate how this trend contributes to the establishment of equilibrium.

Because product concentration increases, allowing the reverse reaction to proceed.

📘 Explanation: As products accumulate, they begin reacting to form reactants. This rise in reverse reaction rate continues until it matches the forward rate—establishing dynamic equilibrium.

7. Compare the roles of reactant concentration at the start of a reaction and reaction reversibility in determining how quickly equilibrium is reached. Which has a greater impact and why?

Reaction reversibility, because it allows both directions to balance.

📘 Explanation: While initial concentration affects speed, reversibility is essential for equilibrium to even occur. Without it, the system can’t balance forward and reverse reactions.

8. How does understanding dynamic equilibrium improve our ability to manipulate chemical reactions in industrial or laboratory settings? Evaluate its practical significance.

It enables control over yield and conditions by shifting equilibrium.

📘 Explanation: Knowledge of equilibrium allows chemists to adjust temperature, pressure, or concentration to favor product formation—crucial in optimizing industrial processes like the Haber process.

9. Is the concept of dynamic equilibrium more useful for explaining physical systems (like phase changes) or chemical systems (like reactions)?

Chemical systems, because they involve concentration and reaction rates.

📘 Explanation: While equilibrium applies to both, chemical systems showcase its full complexity—rate balancing, concentration stability, and energy shifts—making it more analytically rich.

Evaluate the statement: “Equilibrium is a balance, not a standstill.” How does this perspective shape our understanding of reaction dynamics and system behavior?

It emphasizes that reactions continue at equal rates, maintaining balance.

📘 Explanation: Dynamic equilibrium means reactions are ongoing, but their effects cancel out. This insight helps us understand that chemical systems are active, not static.