Thermodynamic and Kinetic Control

Multiple Choice

2H₂O₂(aq) → 2H₂O(l) + O₂(g) ΔG°=−234kJ/mol_rxn

The value of ΔG° for the reaction represented above implies that the decomposition of H₂O₂(aq) is thermodynamically favorable. However, H₂O₂(aq) is typically stable for up to a year stored in a dark bottle at 298K. The best explanation for this observation is that the decomposition reaction

• is only thermodynamically favorable in the presence of a catalyst

• occurs with an increase in entropy because O₂(g) is a product

• is reversible and H₂O₂(aq) is produced almost as fast as it decomposes

• has a slow rate at 298K because the activation energy is relatively high

Multiple Choice

Which of the following forms would have the greatest standard molar entropy?

• H₂(g)

• H₂(l)

• H₂O(g)

• H₂O(l)