Question

By how much does the entropy of $3$ mole of an ideal gas change in going from a pressure of $2$ bar to a pressure of $1$ bar without any change in temperature if surrounding is $1$ bar and $300$k.

Answer 1

$\Delta S=nR\ln \frac{P1}{P2}$

$\Delta S=2.303nR\log \frac{P1}{P2}$

$=2.303\times 3\times .0821\times \log \frac{2}{1}$

$\Delta S=$ $2.303\times 3\times 0.0821\times 0.301$

$\approx 0.1707$