Question

Calculate $Q$ and $w$ for the isothermal reversible expansion of one mole of an ideal gas from an initial pressure of $1.0$ bar to a final pressure of $0.1$ bar at a constant temperature of $273$ $K$ .

• A. $5.22$ $kJ,-5.22$ $kJ$
• B. $-5.22$ $kJ,5.22$ $kJ$
• C. $27.3$ $kJ,-27.3$ $kJ$
• D. $-27.3$ $kJ,27.3$ $kJ$

Answer 1

Answer: (A)

$\Delta w=2.303\times nRTlog\frac{P_1}{P_2}$
$\Delta U=0$
$-q=w$
$w_{rev}=-2.303\times 1\times 8.314\times 273log\frac{1}{0.1}=-5227$ $J$
$w_{rev.}=-5.22$ $kJ$