Final answer:
To calculate ΔGvap at 125°C, use the thermodynamic equation ΔG = ΔH - TΔS with the given enthalpy of vaporization and convert the temperature to Kelvin.
Step-by-step explanation:
To determine the ΔGvap at 125°C, we need to employ the thermodynamic equation ΔG = ΔH - TΔS, where ΔG is the Gibbs free energy change, ΔH is the enthalpy change, and ΔS is the entropy change. Here, we are given the enthalpy of vaporization (ΔHvap) as 61.4 kJ/mol, which we can use to calculate ΔGvap at the given temperature.
First, we need to convert the temperature from °C to K: T(K) = 125°C + 273.15 = 398.15 K. We don’t have the entropy of vaporization (ΔSvap) directly, but if we presume it’s approximately constant near the boiling point, we can use the given ΔHvap and the boiling point temperature to estimate ΔSvap using ΔHvap = TboilΔSvap, and then use this estimated ΔSvap to find ΔGvap at 125°C.