Question

Four cylinders contain equal number of moles of argon, hydrogen, nitrogen and carbon dioxide at the same temperature. The energy is minimum in
(a) argon
(b) hydrogen
(c) nitrogen
(d) carbon dioxide

Answer 1

(a) argon

The energy of a gas is measured as C_vT. All the four cylinders are at the same temperature but the gases in them have different values of C_v, such that it is least for the monatomic gas and keeps on increasing as we go from monatomic to tri-atomic. Among the above gases, argon is monatomic, hydrogen and nitrogen are diatomic and carbon dioxide is tri-atomic. Therefore, the energy is minimum in argon.