The following pictures represent three equilibrium mixtures for the interconversion of A,B,and C molecules (unshaded spheres)into X,Y,and Z molecules (shaded spheres),respectively.What is the sign of ΔG ° for each of the three reactions?

Question

Quizplus · Accepted Answer

Based on Le Chatelier's principle, when the concentration of products is higher (more shaded spheres), the reaction will shift towards the reactants to reach equilibrium. Therefore, for reaction 1, the equilibrium mixture has more A and B molecules than X and Y, indicating that ΔG ° for this reaction is negative. For reaction 2, the equilibrium mixture has more X and Y molecules than A and B, indicating that ΔG ° for this reaction is zero because the system is at equilibrium. For reaction 3, the equilibrium mixture has equal concentrations of all molecules, indicating that ΔG ° for this reaction is positive. Therefore, the best choice is B.

The Following Pictures Represent Three Equilibrium Mixtures for the Interconversion