Question

Calculate the work done (in calorie) by 10 g of an ideal gas of molar mass 16 g in expanding reversibly and isothermally from a volume of 5 L to 15 L at 300 K.

• A. W = $-172.48$ cal
• B. W = $-319.93$ cal
• C. W = $-\mathrm{352.57.}$ cal
• D. W = $-409.37$ cal

Answer 1

The correct option is D W = $-409.37$ cal

Number of moles of ideal gas = $\frac{10}{16}$ mol
R = 1.987 cal $de{g}^{-1}mo{l}^{-1}$ T = 300 K
Final volume $V_2$ = 15 L , initial volume = 5 L
We know,
W = $-2.303nRTlog\frac{V_2}{V_1}$
W = $-2.303\times \frac{10}{16}\times 1.987\times 300\times log3$
W = $-409.37$ cal