A chemist has 2.00 mol of ethanol at its normal boiling point (78.4 °C). The molar enthalpy of vaporization of ethanol is 38.6 kJ mol⁻¹. Which of the following gives the approximate quantity of heat that must be added and the corresponding orientation of the enthalpy arrow on an energy diagram?
a) 3.9×101kJ added; arrow points upward from liquid to vapor.
b) 7.7×101kJ released; arrow points downward from liquid to vapor.
c) 7.7×101kJ added; arrow points upward from liquid to vapor.
d) 7.7×101kJ added; arrow points downward from liquid to vapor.