Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
COMEDK2022ChemistryThermodynamics (C)

The difference between heat capacity at constant pressure and heat capacity at constant volume is

Options

  1. AR
  2. BR T
  3. CR V
  4. D1

Correct answer

A. R

Step-by-step solution

For an ideal gas, the enthalpy H is defined as H = U + PV . Differentiating with respect to temperature T at constant pressure, we have ( H T )_P = ( U T )_P + P ( V T )_P . By definition, C_P = ( H T )_P and C_V = ( U T )_V . For an ideal gas, U depends only on temperature, so ( U T )_P = ( U T )_V = C_V . Using the ideal gas equation PV = nRT , for one mole ( n=1 ), PV = RT . Differentiating with respect to T at constant pressure gives P ( V T )_P = R . Substituting these into the enthalpy derivative equation, we

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 COMEDK PYQs