⚛️ Physics · Kinetic Theory · NEET & JEE

The internal energy of 2 moles of a polyatomic gas with 6 degrees of freedom at 300 K (R = 8.31) is about:

Answer: 14960 J.

A ≈14960 J
B ≈7480 J
C ≈9970 J
D ≈4980 J

Correct answer: A. ≈14960 J

Explanation: U = (f/2)nRT = 3 × 2 × 8.31 × 300 ≈ 14960 J.

Not all gas molecules move at the same speed - the Maxwell-Boltzmann distribution shows the spread, with the most probable speed v_p slightly less than the average v_avg, which is slightly less than the root-mean-square speed v_rms used in the pressure formula.

Concept context

Kinetic theory of gases connects molecular motion to pressure and temperature, explaining gas laws, specific heats, and molecular speeds.

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The internal energy of 2 moles of a polyatomic gas with 6 degrees of freedom at 300 K (R = 8.31) is about:

Concept context

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