Chapter Exam

Chapter 7: Thermodynamics — Online MCQ Test

Q: Which one of the following is an example of an open system?

Answer: B. Boiling water in an open beaker — An open system can exchange both matter and energy with the surroundings. Boiling water in an open beaker loses water vapour and exchanges heat with the surroundings.

Q: Which of the following is a state function?

Answer: C. Internal energy — Internal energy depends only on the initial and final states of the system, not on the path followed. Heat and work are path functions.

Q: If a system absorbs 200 J of heat and does 50 J of work on the surroundings, what is the change in internal energy?

Answer: A. 150 J — Using ΔU = q + w, heat absorbed is +200 J and work done by the system is -50 J. Therefore, ΔU = 200 + (−50) = 150 J.

Q: A reaction has ΔH = -40 kJ mol⁻¹ and ΔS = -100 J mol⁻¹ K⁻¹. At 300 K, which is correct for ΔG?

Answer: A. ΔG is negative and reaction is spontaneous — Convert ΔS to kJ: -100 J mol⁻¹ K⁻¹ = -0.100 kJ mol⁻¹ K⁻¹. Then ΔG = ΔH - TΔS = -40 - 300(−0.100) = -10 kJ mol⁻¹, so it is spontaneous.

Q: Which statement is correct for a reversible isothermal expansion of an ideal gas?

Answer: B. ΔU = 0 — For an ideal gas, internal energy depends only on temperature. In an isothermal process, temperature remains constant, so ΔU = 0.

CHEMISTRY · CLASS 11th · Tamil Nadu State Board

Practice Chapter 7: Thermodynamics with a free chapter-wise online MCQ test for Tamil Nadu State Board CLASS 11th CHEMISTRY. This chapter covers: Focusing on chemical energetics this chapter covers system types state functions first second and third laws of thermodynamics. Students calculate enthalpy changes Hess law applica.... AI-generated questions from basic to board-exam level, with instant results and explanations.

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Chapter 7: Thermodynamics — Important Questions & Answers (FAQ)

Frequently asked questions from Tamil Nadu State Board CLASS 11th CHEMISTRY — Chapter 7: Thermodynamics, with answers and explanations. These are sample questions; the exam has its own separate question set.

Which one of the following is an example of an open system?

A. A sealed steel bomb calorimeter
B. Boiling water in an open beaker ✓
C. Gas enclosed in a rigid container
D. Ice kept in a closed flask

Answer: B. Boiling water in an open beaker
An open system can exchange both matter and energy with the surroundings. Boiling water in an open beaker loses water vapour and exchanges heat with the surroundings.

Which of the following is a state function?

A. Heat
B. Work
C. Internal energy ✓
D. Path length

Answer: C. Internal energy
Internal energy depends only on the initial and final states of the system, not on the path followed. Heat and work are path functions.

If a system absorbs 200 J of heat and does 50 J of work on the surroundings, what is the change in internal energy?

A. 150 J ✓
B. 250 J
C. -150 J
D. -250 J

Answer: A. 150 J
Using ΔU = q + w, heat absorbed is +200 J and work done by the system is -50 J. Therefore, ΔU = 200 + (−50) = 150 J.

A reaction has ΔH = -40 kJ mol⁻¹ and ΔS = -100 J mol⁻¹ K⁻¹. At 300 K, which is correct for ΔG?

A. ΔG is negative and reaction is spontaneous ✓
B. ΔG is positive and reaction is non-spontaneous
C. ΔG is zero and reaction is at equilibrium
D. ΔG cannot be calculated

Answer: A. ΔG is negative and reaction is spontaneous
Convert ΔS to kJ: -100 J mol⁻¹ K⁻¹ = -0.100 kJ mol⁻¹ K⁻¹. Then ΔG = ΔH - TΔS = -40 - 300(−0.100) = -10 kJ mol⁻¹, so it is spontaneous.

Which statement is correct for a reversible isothermal expansion of an ideal gas?

A. ΔU is always positive
B. ΔU = 0 ✓
C. q = 0
D. w = 0

Answer: B. ΔU = 0
For an ideal gas, internal energy depends only on temperature. In an isothermal process, temperature remains constant, so ΔU = 0.

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