Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
MHT CET202123 Sep 2021Morning ShiftChemistryThermodynamics (C)Actual

A monoatomic ideal gas, initially at temperature ' T ₁ ' is enclosed in a cylinder fitted with a frictionless piston. The gas is allowed to expand adiabatically to a temperature ' T ₂ ' by releasing the piston suddenly L₁ and L₂ are the lengths of the gas columns before and after the expansion respectively. The T ₂ ~T ₁ is

Options

  1. A[ L ₁ ~L ₂ ]^ 2 / 3
  2. B[ L ₁ ~L ₂ ]^ 1 / 2
  3. C[ L ₂ ~L ₁ ]^ 1 / 2
  4. D[ L ₂ ~L ₁ ]^ 2 / 3

Correct answer

A. [ L ₁ ~L ₂ ]^ 2 / 3

Step-by-step solution

In an adiabatic process T ₁ ~V ₁⁻¹= T ₂ ~V ₂⁻¹ For an ideal mono atomic gas the no of degree of freedom is 3 aligned & Y =1+ 2 f =1+ 2 3 & T ₁ ~T ₂ = ( V ₂ ~V ₁ )^ Y -1 = ( V ₂ ~V ₁ )^ 2 / 3 = ( L ₂ ~L ₁ )^ 2 / 3 aligned Since volume is proportional to length due to area being constant.

Practice Thermodynamics (C) on Quantrex Academy →

More from Thermodynamics (C)

Identify the INCORRECT statement 2026The standard enthalpies of formation of CH₄ (g), CO₂ (g) and H₂ O(l) are -74.8 kJ mol ⁻¹ , -393.5 kJ mol ⁻¹ and -285.8 kJ mol ⁻¹ respectively. Then the enthalpy change for the give 2026For an ideal gas undergoing an isothermal change, there is 2026Ozone is formed by the reaction O _ 2(g) + O _ (g) O _ 3(g) , H = -107.2 kJ . Given O=O bond energy is 498.0 kJ mol ⁻¹ , the average bond energy of ozone is: 2026H and S for a reaction are 35.5 kJ mol ⁻¹ and 83.6 J K ⁻¹ respectively. Assuming that H and S do not vary with temperature, the reaction is spontaneous when: 2026The heat of combustion of carbon to CO ₂ is -393.5 kJ mol ⁻¹ . The heat released on the formation of 35.2 g of CO ₂ by combustion of C is: 20265 moles of a gas is allowed to pass through a series of changes as shown in the graph, in a cyclic process. The processes C A , B C and A B respectively are 20251 mole of an ideal gas is allowed to expand isothermally and reversibly from 1 L to 5 L at 300 K. The change in enthalpy (in kJ ) is ( R =8.3 ~J ~K ⁻¹ ~mol ⁻¹ ) 2025 Full Thermodynamics (C) list All MHT CET PYQs