Question

One mole of an ideal gas at ${25}^{\circ }C$ expands in volume from 1.0 L to 4.0 L at constant temperature. What work (in J) is done if the gas expands against vacuum ?

• A. $-4.0\times {10}^2$
• B. $-3.0\times {10}^2$
• C. $4.0\times {10}^{2}J$
• D. $0J$

Answer 1

The correct option is D

$0J$

You know that in an irreversible process, $W=-P_{ext}(V_2-V_1)$

The key thing here is that in vaccum $P_{ext}=0$

Hence, $W=0$