Question

What is the change in internal energy of 2 mole of air (Cv = 2.1 X 10^4 J/mole^oC), if its temperature changes from 10^oC to 20^oC?

(a) 420 kJ

(b) 540 kJ

(c) 840 kJ

(d) 1050 kJ

This question was posed to me in unit test.

My question comes from Internal Energy and Energy Conversion Concept in chapter Introduction to Energy Balances for Processes without Reaction and Calculation of Enthalpy Changes of Basic Chemical Engineering

Answer 1

Right choice is (a) 420 kJ

The best I can explain: Change in internal energy = 2*(2.1 X 104)*(20 – 10) = 420 kJ.