JEE Main - Heat capacity Hess's law and enthalpies of various processes One Line Questions & Answers

1. Consider the formation of ammonia from nitrogen and hydrogen: N2(g) + 3H2(g) -> 2NH3(g). If the enthalpy of formation of NH3 is -46.1 kJ/mol, what is the enthalpy change for this reaction? — -92.2 kJ

2. What is the specific heat capacity of water? — 4.184 J/g·K

3. For a diatomic ideal gas, the ratio Cp/Cv is approximately: — 1.4

4. The enthalpy of fusion of ice at 0°C is approximately 6.01 kJ/mol. This means that: — Both (b) and (c)

5. Enthalpy of neutralization is typically defined for the reaction between: — A strong acid and a strong base

6. What is the standard enthalpy of formation of an element in its most stable form at standard conditions? — Zero

7. The enthalpy of hydration refers to the enthalpy change when: — Gaseous ions are surrounded by water molecules.

8. For a given substance, Cp is generally greater than Cv because: — At constant pressure, more heat is needed to achieve the same temperature rise as some energy goes into expansion work.

9. What is the relationship between heat capacity (C) and specific heat capacity (c)? — C = m * c, where m is mass

10. The enthalpy of atomization of methane (CH4) is the enthalpy change for which process? — CH4(g) -> C(g) + 4H(g)

11. Which of the following processes is endothermic? — Melting of ice

12. For an ideal gas, the relationship between Cp and Cv is: — Cp - Cv = R

13. The enthalpy change associated with the formation of gaseous ions from a neutral gaseous atom is called: — Ionization enthalpy

14. If ΔH is negative for a process, it is: — Exothermic

15. Consider the reaction: C(graphite) + O2(g) -> CO2(g), ΔH = -393.5 kJ/mol. This ΔH represents the: — Both (a) and (b)

16. The enthalpy change for the reaction: H2(g) + 1/2 O2(g) -> H2O(l) is -285.8 kJ/mol. This value represents the: — Both (a) and (b)

17. The enthalpy change for the conversion of 1 mole of a liquid into a gas at its boiling point is called: — Enthalpy of vaporization

18. The enthalpy change for the process H2O(l) -> H2O(g) at 100°C is: — Enthalpy of vaporization

19. The enthalpy change for the process Br2(l) -> Br2(g) at its boiling point is: — Enthalpy of vaporization

20. The enthalpy of sublimation is equal to the sum of: — Enthalpy of fusion and enthalpy of vaporization

21. The enthalpy change when 1 mole of a solute dissolves in a solvent to form an infinitely dilute solution is termed: — Enthalpy of solution

22. The enthalpy change when 1 mole of an ionic compound is formed from its gaseous ions is: — Enthalpy of lattice formation

23. The enthalpy change for the conversion of 1 mole of a solid into a liquid at its melting point is known as: — Enthalpy of fusion

24. Which process involves the enthalpy change associated with the formation of 1 mole of a compound from its constituent elements in their standard states? — Enthalpy of formation

25. The enthalpy change for the process H2O(s) -> H2O(l) at 0°C is: — Enthalpy of fusion

26. When an ionic solid dissolves in water, if the lattice enthalpy is greater in magnitude than the hydration enthalpy, the process is: — Endothermic

27. The enthalpy change for the process A(s) -> A(g) is called the enthalpy of: — Sublimation

28. Which of the following is an example of a process with a standard enthalpy of formation equal to zero? — O2(g) -> O2(g)

29. Which type of heat capacity is relevant for reactions occurring at constant volume? — Heat capacity at constant volume (Cv)

30. Which of the following has the highest molar heat capacity at constant pressure? — Water (H2O)

31. If Cp > Cv, it implies that during heating at constant pressure, some energy is used for: — Doing work on the surroundings

32. Which of the following is a unit of heat capacity? — J/K

33. According to Hess's Law, if a reaction is multiplied by a factor 'n', the enthalpy change is also multiplied by: — n

34. The enthalpy of combustion is always: — Negative

35. Kirchhoff's Law relates the change in enthalpy of a reaction to: — Temperature

36. Which of the following is an example of an endothermic process? — Photosynthesis

37. Hess's Law allows us to calculate enthalpy changes for reactions that are: — Irreversible

38. What is the definition of heat capacity? — The amount of heat required to raise the temperature of a substance by 1 degree Celsius.

39. Which of the following represents the enthalpy of lattice formation for an ionic compound? — The energy released when gaseous ions combine to form a solid ionic lattice.

40. What does Hess's Law state? — The enthalpy change for a reaction is independent of the pathway taken.

41. What is the enthalpy of atomization? — The enthalpy change when 1 mole of a substance is converted into its constituent gaseous atoms.

42. What is the enthalpy of combustion? — The enthalpy change when 1 mole of a substance reacts completely with oxygen.

43. If a reaction can be carried out in multiple steps, the total enthalpy change is the sum of the enthalpy changes of the individual steps according to: — Hess's Law

44. What is the molar heat capacity of a substance? — The heat capacity per mole of substance.

45. The heat capacity of a system is defined as the ratio of heat added to: — The resulting temperature change

46. If a reaction is reversed, the sign of the enthalpy change is: — Opposite

47. Hess's Law is particularly useful for calculating the enthalpy change of reactions that are: — Difficult to carry out directly

48. Which of the following has the lowest specific heat capacity? — Sand

49. Hess's Law is a direct consequence of which law of thermodynamics? — First Law

50. Consider the reaction: A -> B. If this reaction can be achieved in two steps, A -> C and C -> B, with enthalpy changes ΔH1 and ΔH2 respectively, then according to Hess's Law, the enthalpy change for A -> B is: — ΔH1 + ΔH2

Heat capacity Hess's law and enthalpies of various processes - One Line Questions