Question

Two moles of helium gas expanded isothermally and irreversibly at $27^{o} \text{C}$ from volume $1 \, dm^{3}$ to $1 \, m^{3}$ at constant pressure of $\text{100 k Pa}.$ Calculate the work done.

• A. $\text{99900 J}$
• B. $- \text{99900 J }$
• C. $\text{34464} \text{.65 J}$
• D. $- \text{34464} \text{.65 J}$

Answer 1

Answer: (B)

$\text{W}=-\text{P∆}V$

Given, $\text{P} = \, 1 0 0 \text{ k} \text{Pa} = 1 0^{5} \text{Pa}$

$\text{V}_{1}=1\text{ d}\text{m}^{3}=10^{- 3}\text{m}^{3},\text{V}_{2}=1\text{ m}^{3}$

$\mathrm{W}=-10^5 \times\left(1-10^{-3}\right) \mathrm{J}$

$\therefore \text{ W} = - \, 99900 \, \text{J}$