Question

Calculate the standard enthalpy change for the vaporization of 15 grams of water given that the molar enthalpy of vaporization of water is 40.7 kJ/mol.

Answer 1

To calculate the standard enthalpy change for the vaporization of 15 grams of water, we first need to determine the number of moles of water present. The molar mass of water is 18.015 g/mol.Number of moles = mass / molar massNumber of moles = 15 g / 18.015 g/mol = 0.8325 molNow, we can use the molar enthalpy of vaporization to find the total enthalpy change.Standard enthalpy change = number of moles  molar enthalpy of vaporizationStandard enthalpy change = 0.8325 mol  40.7 kJ/mol = 33.88 kJThe standard enthalpy change for the vaporization of 15 grams of water is 33.88 kJ.