PYQ Vault
EbooksTutor

Heat, work and internal energy at constant pressure (Q : dU : W = Cp : Cv : R)

This type of question, asked 11 times: 2021 Paper 3, 2021 Paper 24, 27 Jun 2022, 26 Jul 2022, 28 Jul 2022, 31 Jan 2023, 1 Feb 2024, 8 Apr 2024, 24 Jan 2025, 21 Jan 2026 S2, 2 Apr 2026 S1. All 11 questions below, oldest first.

Try each one first, then open its answer.

  1. Question 1

    2021 Paper 3

    4
    A diatomic gas, having Cp=72RC_{p}=\frac{7}{2}R and Cv=52RC_{v}=\frac{5}{2}R, is heated at constant pressure. The ratio dU:dQ:dWdU:dQ:dW

    Tap an option to check your answer.

  2. Question 2

    2021 Paper 24

    21
    The temperature of 3.00 mol3.00\text{ }mol of an ideal diatomic gas is increased by 40.0∘C40.0^{\circ}C without changing the pressure of the gas. The molecules in the gas rotate but do not oscillate. If the ratio of change in internal energy of the gas to the amount of workdone by the gas is x10\frac{x}{10}. Then the value of xx (round off to the nearest integer) is (Given R=8.31 J mol−1 K−1R = 8.31\text{ }J{\text{ }mol}^{- 1}{\text{ }K}^{- 1} )

  3. Question 3

    27 Jun 2022

    113
    A diatomic gas (γ=1.4)(\gamma= 1.4) does 400 J400\text{ }J of work when it is expanded isobarically. The heat given to the gas in the process is ____\_\_\_\_ J.

  4. Question 4

    26 Jul 2022

    13
    7 mole of certain monoatomic ideal gas undergoes a temperature increase of 40 K40\text{ }K at constant pressure. The increase in the internal energy of the gas in this process is (Given R=8.3JK−1 mol−1R = 8.3JK^{- 1}{\text{ }mol}^{- 1} )

    Tap an option to check your answer.

  5. Question 5

    28 Jul 2022

    114
    At a certain temperature, the degrees of freedom per molecule for gas is 8 . The gas performs 150 J150\text{ }J of work when it expands under constant pressure. The amount of heat absorbed by the gas will be ____\_\_\_\_ J.

  6. Question 6

    31 Jan 2023

    93
    Heat energy of 735 J735\text{ }J is given to a diatomic gas allowing the gas to expand at constant pressure. Each gas molecule rotates around an internal axis but do not oscillate. The increase in the internal energy of the gas will be:

    Tap an option to check your answer.

  7. Question 7

    1 Feb 2024

    94
    A diatomic gas (γ=1.4)(\gamma = 1.4) does 200 J200\text{ }J of work when it is expanded isobarically. The heat given to the gas in the process is:

    Tap an option to check your answer.

  8. Question 8

    8 Apr 2024

    110
    A diatomic gas (γ=1.4)(\gamma= 1.4) does 100 J100\text{ }J of work in an isobaric expansion. The heat given to the gas is:

    Tap an option to check your answer.

  9. Question 9

    24 Jan 2025

    25
    The temperature of 1 mole of an ideal monoatomic gas is increased by 50∘C50^{\circ}C at constant pressure. The total heat added and change in internal energy are E1E_{1} and E2E_{2}, respectively. If E1E2=x9\frac{E_{1}}{E_{2}}=\frac{x}{9} then the value of xx is____

  10. Question 10

    21 Jan 2026 S2

    25
    A diatomic gas (γ=1.4)(\gamma = 1.4) does 100 J of work when it is expanded isobarically. Then the heat given to the gas ____\_\_\_\_ J.

  11. Question 11

    2 Apr 2026 S1

    8
    Heat is supplied to a diatomic gas at constant pressure. Then the ratio of ΔQ:ΔU:ΔW\Delta Q:\Delta U:\Delta W is ____\_\_\_\_ .

    Tap an option to check your answer.