Question

The entropy (in $JK ^{-1}$ ) of mixing of $100\, g\, N _{2} O$ at $120^{\circ} C$ and $1.5$ bar with $100\, g$ of $CO _{2}$ at $120^{\circ} C$ and $1.5$ bar is $(\log 2=0.300)$

Answer 1

$\Delta S _{\text {mixing }}=-\left[ n _{1} R \ln X _{1}+ n _{2} R \ln X _{2}\right]$
$=-\left[\frac{100}{44} \times 8.315 \ln \frac{1}{2}+\frac{100}{44} \times 8.315 \ln \frac{1}{2}\right]$
$=+\frac{100}{44} \times 8.135 \times 2.303 \log 2=26.19 \frac{ J }{ K }$