Calculate the mass ( g ) of propane gas ($C_3H_8$) contained in a flask of $50$ litres , at $25^oC$, under a pressure of $7.5$ atm !
$n=\frac{m}{M}$ n: number of moles m: mass M: molar mass
$n$ $=$ $\frac{P\cdot V}{R\cdot T}$ $=$ $\frac{7,5\cdot 50}{0,082\cdot 298}mol$ $m$ $=$ $n\cdot M$ $=$ $\frac{P\cdot V\cdot M}{R\cdot T}$ $=$ $\frac{7,5\cdot 50\cdot 44}{0,082\cdot 298}$ $=$ $675g$
