Final answer:
The sign of the ΔG value for a reaction is reversed if the reaction is reversed, corresponding to the reversal of other thermodynamic variables such as ΔH.
Step-by-step explanation:
If a reaction is reversed, the sign of its ΔG value is reversed. This represents that all thermodynamic variables, including Gibbs free energy (ΔG), enthalpy (ΔH), and entropy (ΔS), are state functions, meaning they depend only on the initial and final states of a system, not on the path taken. Therefore, if you reverse the direction of a chemical reaction, the sign of the ΔH for that reaction also reverses. This concept follows from the Gibbs free energy equation, ΔG° = ΔH° - TΔS°, implying that if the direction of the reaction is reversed, the sign of ΔG would indeed reverse, just as with ΔH.