Question

What is the difference between higher heating value and lower heating value if the product has 5 moles of H2O and Enthalpy of vaporization is 10 J/mole at standard conditions?

(a) 10 J

(b) -10 J

(c) 50 J

(d) -50 J

This question was posed to me in an interview for job.

This intriguing question originated from Heat of Combustion topic in division Application of Energy Balances in the Absence of Chemical Reactions and Energy Balances: How to Account for Chemical Reaction of Basic Chemical Engineering

Answer 1

Correct answer is (c) 50 J

To explain I would say: HHV – LHV = 5*10 = 50 J.