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MHT CET202617 April 2026Evening ShiftChemistryThermodynamics (C)Actual

Calculate the quantity of heat released from system when 2 moles of and ideal gas compressed isothermally from volume 25 dm ^3 to 10 dm ^3 at constant external pressure 4 bar.

Options

  1. A5 5 kJ
  2. B5 0 kJ
  3. C6 5 kJ
  4. D6 0 kJ

Correct answer

D. 6 0 kJ

Step-by-step solution

For an isothermal process of an ideal gas, the change in internal energy U = 0 . From the first law of thermodynamics: U = q + w q = -w The work done during irreversible compression at a constant external pressure is given by: w = -P_ ext V = -P_ ext (V₂ - V₁) Given: P_ ext = 4 bar V₁ = 25 dm ^3 V₂ = 10 dm ^3 Substituting the values: w = -4 (10 - 25) = 60 bar dm ^3 Since 1 bar dm ^3 = 100 J : w = 60 100 J = 6000 J = 6.0 kJ Therefore, q = -6.0 kJ . The quantity of heat released from the system is 6.0 kJ . Answer: 6

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