Question

2 Kg of steam that contains an internal energy of 20 J/Kg, if 50 J of heat is supplied to the system, what is the resultant internal energy of the system?

(a) 45 J/Kg

(b) 40 J/Kg

(c) 35 J/Kg

(d) 20 J/Kg

I had been asked this question during a job interview.

Origin of the question is Energy balance for Different type of systems in chapter Miscellaneous of Chemical Process Calculation

Answer 1

Right answer is (a) 45 J/Kg

The explanation: 50 = 2(U – 20).