NEET UG · Chemistry

Thermodynamics and Thermochemistry

17 practice questions, each with the answer and an explanation.

Practise Thermodynamics and Thermochemistry now

Random questions from this topic, one at a time. You see the answer and the explanation straight after each one.

All 17 questions

  1. According to the First Law of Thermodynamics (ΔU = q + w), what is the internal energy change (ΔU) of a system that absorbs 500 J of heat from its surroundings while performing 200 J of expansion work…
  2. How much work is performed when an ideal gas undergoes free expansion into an evacuated chamber (vacuum) under isothermal conditions?
  3. For the combustion of liquid benzene at 298 K: C6H6(l) + 15/2 O2(g) -> 6 CO2(g) + 3 H2O(l), what is the difference between the enthalpy of reaction and internal energy change (ΔH - ΔU)?
  4. Which of the following thermodynamic properties is classified as an intensive property?
  5. Why is the enthalpy of neutralization of any strong acid (such as HCl or HNO3) with any strong base (such as NaOH or KOH) in dilute aqueous solution a constant value equal to -57.1 kJ/mol (-13.7 kcal/…
  6. By thermodynamic convention, which of the following chemical substances has a standard molar enthalpy of formation (ΔfH°) assigned exactly as zero at 298 K and 1 bar?
  7. For the combustion of gaseous methane: CH4(g) + 2 O2(g) -> CO2(g) + 2 H2O(l), given the standard enthalpies of formation:
    ΔfH°(CH4) = -74.8 kJ/mol
    ΔfH°(CO2) = -393.5 kJ/mol
    ΔfH°(H2O(l)) = -285.8 kJ/mo…
  8. What is the relationship between the heat capacity at constant pressure (Cp) and the heat capacity at constant volume (Cv) for one mole of an ideal gas (Mayer's relation)?
  9. Under which combination of enthalpy change (ΔH) and entropy change (ΔS) is a chemical reaction guaranteed to be spontaneous at all temperatures?
  10. If a chemical reaction has ΔH = +30.0 kJ/mol and ΔS = +100.0 J K^-1 mol^-1, at what temperature does the reaction transition from being non-spontaneous to spontaneous?
  11. How is the standard Gibbs free energy change (ΔG°) quantitatively related to the thermodynamic equilibrium constant (K) at temperature T?
  12. According to the Third Law of Thermodynamics, what is the entropy of a pure, perfectly crystalline substance at absolute zero of temperature (0 Kelvin)?
  13. What is the entropy change of the surroundings (ΔSsurr) when an exothermic reaction releases 600 J of heat to the surroundings at a constant temperature of 300 K?
  14. During a reversible adiabatic expansion of an ideal gas, why does the temperature of the gas inevitably decrease?
  15. For the formation of gaseous hydrogen iodide: H2(g) + I2(g) -> 2 HI(g), how does the standard enthalpy of reaction (ΔrH°) compare to the internal energy change (ΔrU°)?
  16. What is the molar entropy of vaporization (ΔSvap) of a liquid that boils at 373 K with an enthalpy of vaporization ΔHvap = 40.66 kJ/mol?
  17. Given the bond dissociation enthalpies: C-H = 414 kJ/mol, Cl-Cl = 242 kJ/mol, C-Cl = 328 kJ/mol, and H-Cl = 431 kJ/mol, what is the enthalpy change (ΔrH°) for the chlorination reaction: CH4(g) + Cl2(g…

Keep practising

More NEET UG topics

All NEET UG practice →

Ready for the full NEET UG test?

Take a mock testNEET UG hub