Reversible reactions are those where products can convert back into reactants.
Represented using two opposing half arrows (⇌).
Dynamic Equilibrium
Dynamic equilibrium occurs in a closed system where:
The forward and reverse reactions occur at the same rate.
Concentrations of reactants and products remain constant, not necessarily equal.
Characteristics of Dynamic Equilibrium
In a closed system, no reactants or products escape, allowing equilibrium to be established.
In an open system, equilibrium cannot be maintained as reactants/products are lost (e.g., gases in open containers).
Achieving equilibrium when using solutions in open flasks is possible due to negligible evaporation losses.
When gases are involved, a closed system is essential for equilibrium.
Misconceptions
A common error is thinking concentrations of reactants and products are equal at equilibrium; they are constant but not equal.
System Types
Closed System: No matter or energy can escape; essential for equilibrium in gaseous reactions.
Open System: Allows matter and energy to be lost, preventing equilibrium.
Visuals
Various diagrams illustrate the states of equilibrium, showing stable concentrations over time once equilibrium is achieved.
Conclusion
Dynamic equilibrium is a balance of reaction rates in a closed system, maintaining constant concentrations of reactants and products. Understanding the concepts of reversible reactions and dynamic equilibrium is crucial for mastering chemical equilibrium in A-level chemistry.