Question

For an open unsteady state system, 10 J of heat was supplied and 10 J of work was done by the system, what is the value of a change in enthalpy?

(a) 0

(b) 10 J

(c) 20 J

(d) – 20 J

This question was addressed to me during an interview.

This intriguing question originated from Vaporization and Energy Balances for Open, Unsteady-State Systems topic in section Introduction to Energy Balances for Processes without Reaction and Calculation of Enthalpy Changes of Basic Chemical Engineering

Answer 1

Right choice is (a) 0

Explanation: ∆H = 10 – 10 = 0.