NEET Chemistry: Molar heat capacity Practice Questions
6 free multiple-choice questions on Molar heat capacity (Chemical Thermodynamics) for NEET Chemistry, each with the correct answer and a step-by-step explanation. Attempt a question, then reveal the solution to check your reasoning.
Practice thousands more NEET questions in the app →Q1. For an ideal gas undergoing an infinitesimal change in volume at constant pressure, which of the following statements correctly describes the relationship between molar heat capacity at constant volume (Cᵥ) and molar heat capacity at constant pressure (Cₚ)?
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Correct answer: D — Cₚ - Cᵥ = R
For any ideal gas, the relationship between molar heat capacity at constant pressure (Cₚ) and molar heat capacity at constant volume (Cᵥ) is given by Mayer's relation: Cₚ - Cᵥ = R, where R is the universal gas constant.
Q2. The rotational degrees of freedom of a molecule contribute to which component of the molar heat capacity of a diatomic gas?
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Correct answer: B — To both Cₚ and Cᵥ equally
Rotational modes contribute to the internal energy regardless of whether the volume is constant (which defines Cᵥ) or pressure is constant (which defines Cₚ). Therefore, rotational energy contributes to both Cᵥ and Cₚ.
Q3. If the internal energy of a substance changes by ΔU = 100 J at constant volume, what is the corresponding heat absorbed if the process is isobaric (constant pressure)?
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Correct answer: D — 300 J
While ΔU is defined at constant volume, the heat absorbed (Q) at constant pressure is related by Q = ΔU + PΔV. If we consider the general concept where Cₚ > Cᵥ, the heat capacity at constant pressure (Cₚ) will be larger than the heat capacity at constant volume (Cᵥ), implying more heat is required for the same energy change under different constraints. (Conceptually, Qₚ > Qᵥ).
Q4. If the process undergone by an ideal gas is isothermal and isobaric (constant temperature and pressure), the heat absorbed by the gas is related to Cₚ and Cᵥ by which equation?
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Correct answer: D — Q = Cₚ ΔT
For an isobaric process, the heat absorbed is calculated using Cₚ: Q = Cₚ ΔT.
Q5. The heat capacity of a substance is defined as the amount of heat required to raise its temperature by one degree. What is the unit of molar heat capacity?
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Correct answer: A — Joules/mole/Kelvin
Molar heat capacity is defined as the heat capacity per mole. Since heat capacity is energy (Joules) divided by temperature change (Kelvin), the unit for molar heat capacity is Joules per mole per Kelvin (J/mol·K).
Q6. In the context of the equipartition theorem for an ideal gas molecule, which mode of energy transfer is primarily associated with the translational kinetic energy?
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Correct answer: D — Translational kinetic energy
According to the equipartition theorem, each degree of freedom contributes 1.5R to the internal energy. Translational motion corresponds directly to the movement of the molecule across the container, which is related to translational kinetic energy.
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