Question

Determine the standard enthalpy change for the vaporization of 50g of ethyl alcohol (C2H5OH) at its normal boiling point of 78.4°C. Given that the molar heat of vaporization of ethyl alcohol is 38.56 kJ/mol and the molar mass of ethyl alcohol is 46.07 g/mol.

Answer 1

To determine the standard enthalpy change for the vaporization of 50g of ethyl alcohol, we first need to calculate the number of moles of ethyl alcohol in 50g.Number of moles = mass / molar massNumber of moles = 50g / 46.07 g/mol = 1.085 molesNow, we can use the molar heat of vaporization to calculate the enthalpy change.Enthalpy change = number of moles  molar heat of vaporizationEnthalpy change = 1.085 moles  38.56 kJ/mol = 41.83 kJTherefore, the standard enthalpy change for the vaporization of 50g of ethyl alcohol at its normal boiling point of 78.4C is 41.83 kJ.