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COMEDK2024ChemistryThermodynamics (C)Actual

The correct option for free expansion of an ideal gas under adiabatic condition is:

Options

  1. Aq =0, T 0, w =0
  2. Bq 0, T =0, w =0
  3. Cq =0, T =0, w =0
  4. Dq =0, T <0, w 0

Correct answer

C. q =0, T =0, w =0

Step-by-step solution

Free expansion of an ideal gas occurs against vacuum, which implies that the external pressure P_ ext = 0 . The work done in the process is given by w = - P_ ext dV . Since P_ ext = 0 , the work done w = 0 . The process is stated to be adiabatic, which means there is no heat exchange with the surroundings, so q = 0 . According to the first law of thermodynamics, U = q + w . Substituting q = 0 and w = 0 , we get U = 0 . For an ideal gas, the internal energy U is a function of temperature only, i.e., U = f(T) . There

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