⚛️ Physics · Kinetic Theory · NEET & JEE

The internal energy of 2 moles of a monatomic ideal gas at 300 K (R = 8.31 J/mol·K) is about:

Answer: 7.48 kJ.

A 3.74 kJ
B 4.99 kJ
C 7.48 kJ
D 12.5 kJ

Correct answer: C. 7.48 kJ

Explanation: U = (3/2)nRT = 1.5·2·8.31·300 ≈ 7480 J ≈ 7.48 kJ.

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 monatomic ideal gas at 300 K (R = 8.31 J/mol·K) is about:

Concept context

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