Chemical Thermodynamics Quiz - ICSE Class 11 Chemistry

Free practice quiz: Chemical Thermodynamics (ICSE Class 11 Chemistry). 45 multiple-choice questions with answers and explanations. Play online, no sign-up needed.

This ICSE Class 11 Chemistry practice quiz has 45 multiple-choice questions on Chemical Thermodynamics, and 45 of them come with an explanation. Try the 5 sample questions below (tap an option to check yourself), then play the full quiz online. No sign-up needed.

Sample questions

1. For a process to be spontaneous at constant temperature and pressure, the correct thermodynamic condition is:

   1. ΔG > 0
   2. ΔG < 0
   3. ΔG = 0
   4. ΔH < 0
   Show answer

   Answer: B. ΔG < 0

   Gibbs Free Energy (ΔG) is the criterion for spontaneity at constant temperature and pressure. A process is spontaneous if ΔG is negative (ΔG < 0), non-spontaneous if ΔG is positive (ΔG > 0), and at equilibrium if ΔG is zero (ΔG = 0).

2. Which statement best describes the second law of thermodynamics?

   1. Energy can be created or destroyed.
   2. The entropy of an isolated system never decreases.
   3. The total energy of an isolated system is constant.
   4. The entropy of the universe is always negative.
   Show answer

   Answer: B. The entropy of an isolated system never decreases.

   The second law of thermodynamics states that the total entropy of an isolated system can only increase over time, or remain constant in ideal cases where the system is in a steady state or undergoing a reversible process. It essentially means that natural processes tend to move towards greater disorder.

3. A process is endothermic and spontaneous at all temperatures. What can be said about ΔH and ΔS?

   1. ΔH > 0, ΔS > 0
   2. ΔH < 0, ΔS < 0
   3. ΔH > 0, ΔS < 0
   4. ΔH < 0, ΔS > 0
   Show answer

   Answer: A. ΔH > 0, ΔS > 0

   For a process to be spontaneous, ΔG < 0. The equation is ΔG = ΔH - TΔS. If the process is endothermic, ΔH > 0. For it to be spontaneous at all temperatures, the -TΔS term must be sufficiently negative to overcome the positive ΔH. This means ΔS must be positive (ΔS > 0).

4. The conversion of diamond to graphite at 298 K is an endothermic process (ΔH > 0). However, it is spontaneous. Which of the following must be true?

   1. ΔS > 0
   2. ΔS < 0
   3. ΔG < 0
   4. TΔS > ΔH
   Show answer

   Answer: D. TΔS > ΔH

   For a spontaneous process, ΔG < 0. The Gibbs free energy equation is ΔG = ΔH - TΔS. Since ΔH is positive, for ΔG to be negative, the term -TΔS must be more negative than ΔH is positive. This implies that TΔS must be positive and greater than ΔH.

5. Which of the following thermodynamic cycles involves the isothermal compression of a gas, adiabatic expansion of the gas, isothermal expansion of the gas, and adiabatic compression of the gas?

   1. Carnot cycle
   2. Rankine cycle
   3. Otto cycle
   4. Diesel cycle
   Show answer

   Answer: A. Carnot cycle

   The Carnot cycle is a theoretical thermodynamic cycle that describes the most efficient possible heat engine operating between two temperature reservoirs. It consists of four reversible processes: two isothermal processes and two adiabatic processes.

More questions in this quiz

Answers and explanations are in the full quiz.

1. Which of the following statements is always true for an exothermic reaction?
2. For the reaction: N₂(g) + 3H₂(g) ⇌ 2NH₃(g), ΔH = -92.4 kJ/mol. If ΔS = -198.7 J/mol·K at 298 K, what is the value of ΔG for this reaction?
3. Which thermodynamic quantity is a measure of the randomness or disorder of a system?
4. The enthalpy of fusion of water is 6.01 kJ/mol at 0°C. What is the entropy change for the melting of ice at 0°C?
5. For a reversible process at constant temperature and pressure, which of the following is true?
6. Which of the following is NOT a state function?
7. The formation of a stable bond between two atoms is generally associated with:
8. Consider a process where ΔH < 0 and ΔS < 0. For this process to be spontaneous, the temperature must be:
9. For an adiabatic process, which of the following is true?
10. What is the heat capacity at constant volume (Cv) for an ideal monatomic gas?
11. Which of the following is a consequence of the third law of thermodynamics?
12. For the reaction A(g) → B(g), ΔH° = -10 kJ/mol and ΔS° = -50 J/mol·K. At what temperature will this reaction become spontaneous?
13. If a system absorbs heat and does work on the surroundings, then:
14. The standard enthalpy of formation of an element in its most stable form at standard conditions is:
15. For the reaction A(g) + B(g) → C(g), the entropy change (ΔS) is likely to be:
16. Which of the following statements about enthalpy is correct?
17. What is the standard enthalpy change for the formation of 1 mole of a compound from its constituent elements in their standard states?
18. Consider the reaction CO(g) + 1/2 O₂(g) → CO₂(g), ΔH° = -283 kJ/mol. This reaction is:
19. Which of the following is a consequence of the first law of thermodynamics?
20. For a process at constant temperature and volume, the driving force for spontaneity is given by:
21. What is the molar heat capacity at constant pressure (Cp) for an ideal diatomic gas?
22. The entropy change of the universe for a spontaneous process is:
23. Which of the following expressions represents the change in enthalpy of a system during an isothermal process where only P-V work is done?
24. For a reaction at equilibrium, which of the following is true?
25. Which of the following thermodynamic quantities is most directly related to the maximum amount of non-PV work that can be obtained from a system at constant temperature and pressure?
26. For a process occurring at constant temperature, ΔH = TΔS, this indicates that:
27. The internal energy of an ideal gas is a function of:
28. Which of the following is true for sublimation of a solid?
29. If ΔH is positive and ΔS is positive for a reaction, the reaction will be spontaneous:
30. What is the work done by an ideal gas during isothermal expansion from volume V₁ to V₂?
31. Which thermodynamic law dictates that it is impossible to reach absolute zero in a finite number of steps?
32. The enthalpy change for a phase transition at constant temperature and pressure is equal to:
33. Consider the reaction H₂(g) + I₂(g) ⇌ 2HI(g). If the standard enthalpy of formation of HI is +26.5 kJ/mol, what is the enthalpy change for the reaction at standard conditions?
34. A system undergoes a process where heat is added to the system (Q > 0) and the system performs work on the surroundings (W > 0). The change in internal energy (ΔU) will be:
35. Which of the following statements is INCORRECT regarding entropy?
36. For an ideal gas undergoing an adiabatic process, which relationship holds true?
37. What is the value of the adiabatic index (γ) for a monatomic ideal gas?
38. The Gibbs free energy change (ΔG) for a reaction is +17.3 kJ/mol. The entropy change (ΔS) is +28 J/mol·K. At what temperature will this reaction become spontaneous?
39. Which thermodynamic quantity is related to the absolute value of entropy?
40. For the reaction A(g) + B(g) → AB(g), if the enthalpy change is negative and the entropy change is negative, the reaction will be most spontaneous at:

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