Is my answer correct for finding the change in entropy?

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The discussion centers on calculating the change in entropy for an ideal gas undergoing reversible compression at constant temperature. The user initially presents the formula for entropy change, S=n Cv ln(T2/T1) + nR ln(V2/V1), and simplifies it to S=nR ln(V2/V1) due to constant temperature. They substitute V2/V1 with 1/3, reflecting the pressure increase to three times the initial value. Participants are asked to confirm the correctness of this approach and calculation. The focus remains on verifying the entropy change formula and its application in this specific scenario.
aruwin
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I am not sure if my work is correct so I need your help to confirm it.

Question:
Find the change in entropy when:

n mol of ideal gas (ɣ=7/5) is reversibly compressed until the pressure is three times the ideal gas at constant temperature.

My answer:
S=n Cv ln(T2/T1) + nR ln(V2/V1)

as temperature is constant so

S=nR ln(V2/V1)
V2/V1=1/3
 
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aruwin said:
I am not sure if my work is correct so I need your help to confirm it.

Question:
Find the change in entropy when:

n mol of ideal gas (ɣ=7/5) is reversibly compressed until the pressure is three times the ideal gas at constant temperature.

My answer:
S=n Cv ln(T2/T1) + nR ln(V2/V1)

as temperature is constant so

S=nR ln(V2/V1)
V2/V1=1/3
Look right to me.

AM
 
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