The standard enthalpy change for the vaporization reaction of ethanol Hvap is the amount of energy required to convert 1 mole of liquid ethanol to its gaseous state at a constant temperature of 298 K. In this case, the enthalpy of vaporization of ethanol is given as 38.56 kJ/mol. The standard enthalpy of formation of liquid ethanol is not relevant to this problem, as it refers to the energy change when 1 mole of ethanol is formed from its constituent elements in their standard states.Therefore, the standard enthalpy change for the vaporization reaction of ethanol at 298 K is 38.56 kJ/mol.