Question

Calculate the standard enthalpy change for the vaporization of 100 g of water at 100°C given that the enthalpy of vaporization of water is 40.7 kJ/mol.

Answer 1

First, we need to convert the mass of water  100 g  into moles. The molar mass of water  HO  is 18.015 g/mol.moles of water = mass / molar massmoles of water = 100 g / 18.015 g/molmoles of water  5.55 molNow, we can use the enthalpy of vaporization  Hvap  to calculate the standard enthalpy change for the vaporization of 100 g of water.H = moles  HvapH = 5.55 mol  40.7 kJ/molH  225.89 kJThe standard enthalpy change for the vaporization of 100 g of water at 100C is approximately 225.89 kJ.