Question

Calculate the entropy change ($inJ{K}^{-1}$) when $220g$ of Carbon dioxide expands reversibly and isothermally from an initial volume of $1litre$ to $100litre$ at $600K$.

• A. $191.4J{K}^{-1}$
• B. $280J{K}^{-1}$
• C. $305.5J{K}^{-1}$
• D. $168J{K}^{-1}$

Answer 1

The correct option is A $191.4J{K}^{-1}$

The change in entropy for the isothermal reversible process is given as:
$△S=2.303nRlog\frac{V_2}{V_1}$
where $V_2$ is the final volume and $V_1$ is the initial volume.
$V_2=100L$
$V_1=1L$
molar mass of $C{O}_2=44g/mol$
so, $molesofgas,n=\frac{220}{44}=5$
Putting all the values we get :
$△S=2.303\times 5\times 8.314\times log\frac{100}{1}=191.4J{K}^{-1}$