Question

What is the enthalpy change of a reaction at 90^oC, if the enthalpy of reactant at 90^oC and 25^oC are 60 J and 25 J, and enthalpy of product at 90^oC and 25^oC are 80 J and 10 J, and the enthalpy change of reaction at 25^oC is 5 J?

(a) 10 J

(b) 50 J

(c) 110 J

(d) 150 J

I had been asked this question in an internship interview.

My question is based upon Heat (Enthalpy) of Reaction 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 option is (c) 110 J

The best I can explain: Heat of reaction = (60 – 25) + (80 – 10) + 5 = 110 J.