The following diagrams represent a hypothetical reaction A ¡ B, with A represented by red spheres and B represented by blue spheres. The sequence from left to right represents the system as time passes. Does the system reach equilibrium? If so, in which diagram(s) is the system in equilibrium? [Sections 15.1 and 15.2]

Verified step by step guidance

1. Step 1: Understand the concept of equilibrium. In a chemical reaction, equilibrium is reached when the rate of the forward reaction (A to B in this case) equals the rate of the reverse reaction (B to A). This means that the concentrations of A and B remain constant over time, even though the reactions are still occurring.
2. Step 2: Look at the diagrams from left to right, which represent the system as time passes. You are looking for the point where the number of red spheres (A) and blue spheres (B) remain constant from one diagram to the next.
3. Step 3: If such a point exists, that is the point at which the system has reached equilibrium. The system is in equilibrium in all diagrams from that point forward.
4. Step 4: If no such point exists, i.e., the number of red and blue spheres is continuously changing from one diagram to the next, then the system does not reach equilibrium.
5. Step 5: Remember that reaching equilibrium does not necessarily mean that the number of A and B are equal. It simply means that their numbers are not changing because the rates of the forward and reverse reactions are equal.

Key Concepts

Chemical Equilibrium

Chemical equilibrium occurs when the rates of the forward and reverse reactions are equal, resulting in constant concentrations of reactants and products over time. In a dynamic equilibrium, the reaction continues to occur in both directions, but there is no net change in the concentrations of A and B. Understanding this concept is crucial for determining whether the system depicted in the diagrams has reached a state of balance.

Reaction Rate

The reaction rate refers to the speed at which reactants are converted into products in a chemical reaction. It can be influenced by various factors, including concentration, temperature, and the presence of catalysts. Analyzing the changes in the concentration of A and B over time in the diagrams helps in assessing whether the system is approaching equilibrium.

Dynamic Nature of Equilibrium

Equilibrium is a dynamic state, meaning that even when the concentrations of reactants and products remain constant, molecular interactions and reactions continue to occur. This concept emphasizes that equilibrium does not imply a cessation of activity but rather a balance between opposing processes. Recognizing this dynamic nature is essential for interpreting the diagrams and identifying the points at which equilibrium is achieved.