Question

Find the work done when 2 mole of hydrogen expand isothermally and reversibly from 15 to 50 litres against a constant pressure of 1 atm at ${25}^{o}C$.

• A. 706.60 cals
• B. 847 K cal
• C. 84.7 cals
• D. 84.7 K cal

Answer 1

The correct option is A 706.60 cals

Given, $n=2$

$V_i=15L$

$V_f=50L$

$T={25}^{o}C=298K$

$P=1atm$

For isothermal work, $W=2.303nRTlog\frac{V_f}{V_i}$

$=2.303\times 1mol\times 1.98calmo{l}^{-1}{K}^{-1}$

$=1358.86\times 0.52cal$

$=706.60cal$