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ChemistryThermodynamics - IIsothermal Process/Isobaric/IsochoricMedium2 minQB

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Passage / Comprehension

The second law of thermodynamics is a fundamental law of science. In this problem we consider the thermodynamics of an ideal gas, phase transition and chemical equilibrium. 3.00 mol of $CO_{2}$ gas expands isothermally (in thermal contact with the surroundings; temperature $= 15. 0^{\circ} C$ ) against a fixed external pressure of 1.00 bar. The initial and final volumes of the gas are 10.0 L and 30.0 L , respectively.

Calculate $Δ S_{sys}$ , assuming $CO_{2}$ to be an ideal gas. (take $ln 3 = 1.1, R = 8.3 J / K$ mole)

Options:

Answer:

Solution:

For an isothermal expansion of an ideal gas:

$Δ S_{sys} = n R ln (\frac{V _{2}}{V _{1}})$

$= 3.00 \times 8.3 \times ln (\frac{30}{10}) = 3 \times 8.3 \times 1.1 = 27.4 J K^{- 1}$

Since the gas expands ( $V_{2} > V_{1}$ ), the entropy of the system increases.

$Δ S_{sys} = 27.4 J K^{- 1}$

Stream:JEESubject:ChemistryTopic:Thermodynamics - ISubtopic:Isothermal Process/Isobaric/Isochoric

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