To calculate the standard enthalpy change for the vaporization of 25 grams of water, we can use the following formula:H = n * Hvapwhere H is the enthalpy change, n is the number of moles of water, and Hvap is the molar enthalpy of vaporization.First, we need to find the number of moles of water n . The molar mass of water H2O is 18.015 g/mol.n = mass / molar massn = 25 g / 18.015 g/moln 1.387 molesNow, we can calculate the enthalpy change:H = n * HvapH = 1.387 moles * 40.7 kJ/molH 56.5 kJThe standard enthalpy change for the vaporization of 25 grams of water at 100 degrees Celsius and 1 atmosphere of pressure is approximately 56.5 kJ.