Question

Calculate the change in entropy for 3 moles of an ideal gas with Cp=(9/2)R and Cv=(7/2)R,...

Calculate the change in entropy for 3 moles of an ideal gas with Cp=(9/2)R and Cv=(7/2)R, undergoing the following quasi-static process. The gas is initially at T=350K, and is being compressed from 4 m3 to 1 m3 in a perfectly insulated container.

Homework Answers

Answer #1

Hi!!

If the system walls are adiabatic (Q = 0), but not rigid (W ? 0), and energy is added to the system in the form of frictionless, non-viscous work, the temperature of the system will rise. The energy added is stored within the system, and is completely recoverable as work. Such a process of the frictionless, non-viscous application of work to a system is called an isentropic process. If the system contains a compressible gas and is reduced in volume, the uncertainty of the position of the gas is reduced as it is compressed to a smaller volume, and seemingly reduces the entropy of the system, but the temperature of the system will rise as the process is isentropic (?S = 0). Should the work be added in such a way that friction or viscous forces are operating within the system, the process is not isentropic, the temperature of the system will rise, and the work added to the system is not entirely recoverable in the form of work.

my regards!!

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