To calculate the standard enthalpy change for the phase transition of ice to water at 1 atm and 25C, we need to consider two steps: 1. Heating the ice from -273.15C 0 K to 0C2. Melting the ice at 0C to form water at 0CSince we are given the enthalpy of fusion Hfus for water as 6.01 kJ/mol, we can use this value for the second step. However, we also need to calculate the enthalpy change for the first step, which involves heating the ice. To do this, we need the specific heat capacity of ice Cp,ice , which is approximately 2.09 J/gK. First, let's convert the temperature difference from Celsius to Kelvin. The temperature difference between -273.15C and 0C is 273.15 K.Next, we need to find the molar mass of water, which is 18.015 g/mol.Now, we can calculate the enthalpy change for heating the ice H1 :H1 = Cp,ice T molar mass of water H1 = 2.09 J/gK 273.15 K 18.015 g/mol H1 = 10242.6 J/molSince we want the answer in kJ/mol, we can convert it:H1 = 10.24 kJ/molNow, we can calculate the total enthalpy change for the phase transition Htotal :Htotal = H1 + HfusHtotal = 10.24 kJ/mol + 6.01 kJ/molHtotal = 16.25 kJ/molTherefore, the standard enthalpy change for the phase transition reaction of ice to water at 1 atm and 25C is 16.25 kJ/mol.