Question

What is the enthalpy of reaction for CH4 + 2O2 -> CO2 + 2H2O, if the conversion of CH4 is 50%, and heat of formation of CH4, O2, CO2, and H2O are 10 J, 0, 6 J and 4 J?

(a) 0

(b) 2 J

(c) 4 J

(d) 6 J

This question was addressed to me by my college director while I was bunking the class.

My doubt stems from Heat (Enthalpy) of Reaction in section 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 (b) 2 J

The best I can explain: Heat of reaction = 2*4*0.5 + 6*0.5 + 10*0.5 – 2*0 – 10 = 4 + 3 + 5 – 10 = 2 J.