Question

5 mole of an ideal gas expand isotherally and irreversibly from a pressure of 10 atm to 1 atm against a contant external pressure of 1 at. Work done at 300 K is:

• A. -15.921 kJ
• B. -11.224 kJ
• C. -110.83 kJ
• D. None of these

Answer 1

The correct option is B

-11.224 kJ

$\int dw=-\int P_{ext}dV$

$W_{irr}=-P_{ext}[\frac{nRT}{P_2}-\frac{nRT}{P_1}]=-[5\times 8.314\times 300][1-\frac{1}{10}]$

$W_{irr}=-11.224kJ$