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KVPY2019ChemistryThermodynamics (C)

During the free expansion of an ideal gas in an isolated chamber,

Options

  1. Ainternal energy remains constant
  2. Binternal energy decreases
  3. Cwork done on the system is negative
  4. Dtemperature increases

Correct answer

A. internal energy remains constant

Step-by-step solution

In a free expansion, external pressure p e x = 0 ∴    W = - p ex · Δ V = 0 and the system is isolated. Heat does not enter or leave, q = 0 Δ U = q + W = 0 , where U = internal energy.

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