∆G° is?

∆G° is?

• A. The energy change for a reaction at standard temperature
• B. The energy change under nonstandard conditions
• C. The Gibbs Free Energy at any condition
• D. The Gibbs Free Energy under standard conditions which are 298K, 1.0 atm, and 1.0 M

Answer: (D)

ΔG° is the Gibbs free energy change for a reaction when all reactants and products are in their standard states—1 M for solutes, 1 atm for gases—at the standard temperature of 298 K. This standard-state value serves as a reference point, allowing us to compare different reactions and relate to the equilibrium constant via ΔG° = -RT ln K. It reflects the energy change independent of the path taken, depending only on the initial and final states under those standard conditions. It is not the energy change under nonstandard conditions—that would be ΔG with actual concentrations—nor is it Gibbs free energy at any condition, which is ΔG that varies with conditions.

ΔG° is the Gibbs free energy change for a reaction when all reactants and products are in their standard states—1 M for solutes, 1 atm for gases—at the standard temperature of 298 K. This standard-state value serves as a reference point, allowing us to compare different reactions and relate to the equilibrium constant via ΔG° = -RT ln K. It reflects the energy change independent of the path taken, depending only on the initial and final states under those standard conditions. It is not the energy change under nonstandard conditions—that would be ΔG with actual concentrations—nor is it Gibbs free energy at any condition, which is ΔG that varies with conditions.