Q1. Which of the following processes increases the entropy of the system? (2022)
Solution:
The melting of ice increases the entropy of the system as it transitions from a solid to a liquid state, which has more disorder.
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Q2. In a reversible process, the work done is: (2023)
Solution:
In a reversible process, the work done is always maximum compared to irreversible processes.
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Q3. What does the term 'enthalpy' (H) represent? (2019)
Solution:
Enthalpy (H) represents the total heat content of a system at constant pressure and is defined as internal energy plus pressure-volume work.
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Q4. In thermodynamics, the term 'system' refers to: (2022)
Solution:
In thermodynamics, the 'system' refers to the part of the universe that is being studied, while the surroundings are everything else.
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Q5. Which of the following is NOT a characteristic of an exothermic reaction? (2019)
Solution:
An exothermic reaction releases heat and has a negative ΔH. It causes the temperature of the surroundings to increase, not absorb energy.
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Q6. What is the change in internal energy (ΔU) for an isothermal process for an ideal gas? (2021)
Solution:
In an isothermal process for an ideal gas, the temperature remains constant, which means the internal energy does not change. Therefore, ΔU = 0.
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Q7. Which of the following processes has a positive change in entropy? (2023)
Solution:
The melting of ice has a positive change in entropy as the solid structure becomes more disordered in the liquid state.
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Q8. What is the change in internal energy (ΔU) for an isothermal process of an ideal gas? (2021)
Solution:
In an isothermal process for an ideal gas, the temperature remains constant, which means the internal energy does not change. Therefore, ΔU = 0.
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Q9. What is the standard enthalpy change (ΔH°) for the reaction: C(s) + O2(g) → CO2(g)? (2022)
Solution:
The standard enthalpy change for combustion reactions, such as the formation of CO2 from carbon and oxygen, is typically negative, indicating that the reaction is exothermic.
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Q10. In which of the following conditions does the entropy of a system increase? (2022)
Solution:
The entropy of a system increases when a solid melts into a liquid, as the disorder of the system increases.
