A gas mixture consists of 2 moles of O₂ and 4 moles of Ar at temperature T. Neglecting all vibrational modes, the total internal energy of the system is:
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A gas mixture consists of 2 moles of O₂ and 4 moles of Ar at temperature T. Neglecting all vibrational modes, the total internal energy of the system is:

G1 Physics · Accepted Answer

Step 1: O₂ is diatomic with f = 5 (3 translational and 2 rotational modes), neglecting vibrations. Step 2: Internal energy of 2 moles O₂: U₁ = 2 × (5/2)RT = 5RT. Step 3: Ar is monoatomic with f = 3. For 4 moles Ar: U₂ = 4 × (3/2)RT = 6RT. Step 4: U = U₁ + U₂ = 5RT + 6RT = 11RT. Final answer: (D).