Is my answer correct for finding the change in entropy?

[aruwin]

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

 

[Andrew Mason]

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