Question

this question has multiple parts. work all the parts to get the most points.
consider the following generic reaction:
2a₂b(g) ⇌ 2a₂(g) + b₂(g)
some molecules of a₂b are placed in a 1.0 - l container. several snapshots of the reaction mixture are taken and illustrated
which illustration is the first to represent an equilibrium mixture?

Explanation:

Step1: Understand the concept of equilibrium

At equilibrium, the concentrations of reactants and products remain constant. In terms of molecular snapshots, the number of \(A_2B\), \(A_2\) and \(B_2\) molecules should not change further.

Step2: Analyze the snapshots

• In the first snapshot (left - most of the original three), the reaction is still proceeding as the number of molecules of \(A_2B\) is relatively high and the reaction has not reached a state of no - net - change.
• In the second snapshot (middle of the original three), the composition of the mixture (number of \(A_2B\), \(A_2\) and \(B_2\) molecules) is the same as in the third snapshot (right - most of the original three).

Answer:

The middle illustration (the second one among the original three snapshots) is the first to represent an equilibrium mixture.