Question

Carbon monoxide is allowed to expand isothermally and reversibly from $10m^{3}to20m^3$ at $300K$ and work obtained is $4.754kJ$. Calculate the number of moles of carbon monoxide

• A. $27.5mol$
• B. $5.5mol$
• C. $2.75mol$
• D. $55.0mol$

Answer 1

The correct option is C $2.75mol$

Work done in an isothermal reversible process is given as:
$w=-2.303nRTlog\frac{V_2}{V_1}$
Given: $V_1=10m^3$
$V_2=20m^3$
$T=300K$
$R=8.314J/K.mol$
$w=-4.754\times {10}^{3}J$ (as work is done by the system)
So,
$-4.754\times {10}^3=-2.303n\times 8.314\times 300\times log\frac{20}{10}$
Using $log2=0.3010$
On solving we get,
$n=2.75mol$