Question

What is the standard enthalpy change for the vaporization of 50 g of water at its boiling point of 100°C? The molar heat of vaporization for water is 40.7 kJ/mol.

Answer 1

To calculate the standard enthalpy change for the vaporization of 50 g of water, we first need to determine the number of moles of water present. The molar mass of water  H2O  is 18.015 g/mol.Number of moles = mass / molar massNumber of moles = 50 g / 18.015 g/mol = 2.775 molesNow, we can use the molar heat of vaporization  40.7 kJ/mol  to calculate the standard enthalpy change.Standard enthalpy change = number of moles  molar heat of vaporizationStandard enthalpy change = 2.775 moles  40.7 kJ/mol = 112.94 kJThe standard enthalpy change for the vaporization of 50 g of water at its boiling point of 100C is 112.94 kJ.