To calculate the standard enthalpy change for the fusion of 2.5 moles of solid sulfur S8 at its melting point 388 K , we can use the given information:Hfus = 9.73 kJ/mol enthalpy of fusion Sfus = 22.8 J/ mol*K entropy of fusion First, we need to find the enthalpy change for the fusion of 2.5 moles of sulfur. We can do this by multiplying the enthalpy of fusion per mole by the number of moles:H = Hfus * molesH = 9.73 kJ/mol * 2.5 molH = 24.325 kJNow, we have the enthalpy change for the fusion of 2.5 moles of sulfur. However, we also need to account for the heat capacity change during the phase transition. We can do this by using the heat capacities of solid and liquid sulfur and the temperature at which the phase transition occurs:Cp = Cp liquid - Cp solid Cp = 37.05 J/ mol*K - 22.75 J/ mol*K Cp = 14.3 J/ mol*K Now, we can calculate the additional enthalpy change due to the heat capacity change:H_additional = Cp * moles * TH_additional = 14.3 J/ mol*K * 2.5 mol * 388 K - 388 K H_additional = 0 kJSince the temperature remains constant during the phase transition, there is no additional enthalpy change due to the heat capacity change.Finally, we can find the total standard enthalpy change for the fusion of 2.5 moles of solid sulfur:H_total = H + H_additionalH_total = 24.325 kJ + 0 kJH_total = 24.325 kJThe standard enthalpy change for the fusion of 2.5 moles of solid sulfur S8 at its melting point 388 K is 24.325 kJ.