## Fundamentals of Physics Extended (10th Edition)

$\Delta S=14.4\frac{J}{K}$
For an isothemal process, we know that: $T_i=T_f$ We also know that: $\Delta S=S_f-S_i=nR\ln\frac{v_f}{v_i}+nC_v\ln \frac{T_f}{T_i}$ As $\ln \frac{T_f}{T_i}=0$; $\Delta S=nR\ln\frac{v_f}{v_i}$ We plug in the known values to obtain: $\Delta S=2.50(8.31)\ln(2.00)=14.4\frac{J}{K}$