Question

$10$ moles of an ideal gas are expanded isothermally and reversibly from $50L$ to $75L$ at $350K$.

Calculate the maximum work done.

• A. $-\text{9.8 kJ}$
• B. $-\text{11.8 kJ}$
• C. $-\text{13.8 kJ}$
• D. $-\text{15.8 kJ}$

Answer 1

The correct option is B $-\text{11.8 kJ}$

$W_{max}=-2.303nRTlog\frac{V_2}{V_1}$
$W_{max}=-2.303\times \text{10 mol}\times \text{8.314 J/mol/K}\times \text{350 K}\times log\frac{\text{75 L}}{\text{50 L}}$
$W_{max}=-\text{11800 J}$
$W_{max}=-\text{11800 J}\times \frac{\text{1 kJ}}{\text{1000 J}}$
$W_{max}=-\text{11.8 kJ}$
The maximum work done is $-\text{11.8 kJ}$