Question

At $25^{\circ }C,50g$ of iron reacts with $HCl$ to form $FeC{l}_2.$ The evolved hydrogen gas expands against a constant pressure of $1$ bar. The work done by the gas during this expansion is ________ $J$.
(Round off to the Nearest Integer)
[Given: $R=8.314Jmo{l}^{-1}{K}^{-1}.$ Assume,
hydrogen is an ideal gas]
[Atomic mass off Fe is $55.85u$ ]

Answer 1

Answer: 2218

$T=298K,R=8.314\frac{J}{molK}$

$\to$ Chemical reaction is $Fe+2HCl\to FeC{l}_2+H_2(g)$

$50gP=1$ bar

$=\frac{50}{55.85}mol$

$\frac{50}{55.85}mol$

$\to$ Work done for $1mol$ gas $=-P_{ext}\times \Delta V$

$=\Delta ngRT$

$=-1\times 8.314\times 298J$

$\to$ Work done for $\frac{50}{55.85}$ mol of gas

$=-1.8314\times 298\times \frac{50}{55.85}J$

$=-2218.059J$

$=-2218J$