To calculate the heat energy required to melt 25 grams of ice at 0C, we need to use the formula:q = n Hfwhere q is the heat energy, n is the number of moles of ice, and Hf is the enthalpy of fusion of ice.First, we need to find the number of moles of ice. The molar mass of water HO is 18.015 g/mol. To find the number of moles, we can use the formula:n = mass / molar massn = 25 g / 18.015 g/moln 1.387 molesNow, we can use the formula for heat energy:q = n Hfq = 1.387 moles 6.01 kJ/molq 8.34 kJTherefore, the amount of heat energy required to melt 25 grams of ice at 0C is approximately 8.34 kJ.