Question

The q value and work done in an isothermal reversible expansion of one mole of an ideal gas from an initial pressure of 1 bar to a final pressure of $0.1bar$ at constant temperature $273K$ are:

• A. $5.22kJ,-5.22kJ$
• B. $+6.22kJ,6.22kJ$
• C. $5.22J,5.22J$
• D. $-6.22J,-6.22J$

Answer 1

Answer: (A)

$5.22kJ,-5.22kJ$

As we know,

$w=-2.303nRTlog\left(\begin{array}{c}\frac{P_1}{P_2}\end{array}\right)$

$=-2.303\times 1\times 8.314\times 273log\left(\begin{array}{c}\frac{1}{0.1}\end{array}\right)$

$=-5.227kJ$

For isothermal process:
$q=-w$

$=5.227kJ$ for the isothermal process.