Question

A gas mixture consists of 2 moles of oxygen and 4 moles argon at temperature T. Neglecting all vibrational modes, the total internal energy of the system is

• A. 4 RT
• B. 15 RT
• C. 9 RT
• D. 11 RT

Answer 1

The correct option is D

11 RT

Oxygen is diatomic gas, hence its energy of two moles $2\times \frac{5}{2}RT=5RT$

Argon is a monoatomic gas, hence its internal energy of 4 moles = $4\times \frac{3}{2}RT=6RT$

Total Internal energy (6 + 5)RT = 11RT