Question

How are enthalpies of streams calculated?

(a) Relative to the reference state

(b) Absolutely

(c) Depends on the reaction

(d) None of the mentioned

This question was posed to me during a job interview.

My question is taken from Merging Heat of Formation with Sensible Heat of Compound 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

Right answer is (a) Relative to the reference state

To elaborate: Enthalpies of the streams are calculated relative to the reference state.