Given that
The volume of ethanol = 155 mL
Diensity of ethanol = 0.7849 g/mL
Enthalpy of vaporization of the alcohol at 25 oC = 42.32 kJ/mol.
CH3CH2OH (MW = 46.07g/mol)
The mass of ethanol = volume * density
= 155 mL * 0.7849 g/mL
= 121.66 g
The number of moles of ethanol = mass of ethanol / molar mass of ethanol
= 121.66 g / 46.07 g/mol
= 2.64 mol
Quantity of heat energy is required to evaporate 155 mL of the alcohol at 25oC = Enthalpy of vaporization * number of moles of ethanol
= (42.32 kJ/mol.)*2.64 mol
= 111.76 kJ