Thermodynamics and Thermochemistry MCQs

Thermodynamics is the study of energy, heat, and work in physical and chemical processes, while thermochemistry focuses on energy changes in chemical reactions. It helps predict reaction feasibility and energy exchange between systems.

1. In thermodynamics, the system refers to:
   (a) The entire universe
   (b) The part of the universe under study
   (c) The surroundings of an experiment
   (d) A closed container only
   
2. Which of the following is considered the surroundings in thermodynamics?
   (a) The part of the universe under study
   (b) Everything outside the system
   (c) The system itself
   (d) The reaction components only
   
3. Which of the following best describes an open system?
   (a) It allows only energy exchange
   (b) It allows only matter exchange
   (c) It allows both matter and energy exchange
   (d) It does not allow any exchange
   
4. A closed system allows the exchange of:
   (a) Only matter
   (b) Only energy
   (c) Both matter and energy
   (d) Neither matter nor energy
   
5. Which of the following is an example of an isolated system?
   (a) A boiling pot of water
   (b) A thermos flask
   (c) An open beaker of acid
   (d) A car radiator
   
6. The first law of thermodynamics is based on:
   (a) Conservation of mass
   (b) Conservation of energy
   (c) Conservation of temperature
   (d) Conservation of volume
   
7. The second law of thermodynamics states that:
   (a) Energy can neither be created nor destroyed
   (b) Entropy of an isolated system always increases
   (c) At absolute zero, entropy is maximum
   (d) Work done on a system is always negative
   
8. The third law of thermodynamics states that at absolute zero:
   (a) Energy is maximum
   (b) Entropy is zero
   (c) Enthalpy is infinite
   (d) Pressure is zero
   
9. Which equation represents Gibbs free energy?
   (a) ΔG = ΔH – TΔS
   (b) ΔG = ΔH + TΔS
   (c) ΔG = TΔS – ΔH
   (d) ΔG = ΔH x TΔS
   
10. For a spontaneous reaction, Gibbs free energy (ΔG) must be:
    (a) Positive
    (b) Zero
    (c) Negative
    (d) Infinite
    
11. Which of the following correctly describes heat (q) in thermodynamics?
    (a) It is a form of matter
    (b) It is energy transferred due to a temperature difference
    (c) It is stored in molecules
    (d) It is equal to internal energy at all times
    
12. Which of the following represents work (W) in thermodynamics?
    (a) W = PΔV
    (b) W = q + ΔH
    (c) W = q – ΔG
    (d) W = TΔS
    
13. The total internal energy of a system is represented by:
    (a) U = q + W
    (b) U = q – W
    (c) U = q / W
    (d) U = q x W
    

Answer Key

1. (b) The part of the universe under study
2. (b) Everything outside the system
3. (c) It allows both matter and energy exchange
4. (b) Only energy
5. (b) A thermos flask
6. (b) Conservation of energy
7. (b) Entropy of an isolated system always increases
8. (b) Entropy is zero
9. (a) ΔG = ΔH – TΔS
10. (c) Negative
11. (b) It is energy transferred due to a temperature difference
12. (a) W = PΔV
13. (a) U = q + W