Question

Heat of formations of A, B, C, and D, are 5 J, 8 J, 2 J, and 15 J respectively, what is the heat of reaction 3A + B -> 3C + 2D?

(a) 9 J

(b) 10 J

(c) 13 J

(d) 15 J

I got this question at a job interview.

Query is from Standard Heat (Enthalpy) of Formation 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 choice is (c) 13 J

For explanation: Heat of reaction = 2*15 + 3*2 – 8 – 3*5 = 13 J.