Question

What is the enthalpy change of a reaction at 35^oC, if the enthalpy of reactant at 35^oC and 25^oC are 18 J and 10 J, and enthalpy of product at 35^oC and 25^oC are 12 J and 8 J, and the enthalpy change of reaction at 25^oC is 15 J?

(a) 9 J

(b) 14 J

(c) 22 J

(d) 27 J

This question was addressed to me during an internship interview.

Question is from Heat (Enthalpy) of Reaction 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

The correct option is (d) 27 J

The explanation: Heat of reaction = (18 – 10) + (12 – 8) + 15 = 27 J.