Question

A pre-weighed vessel was filled with oxygen at NTP and weighed. It was then evacuated, filled with ${SO}_2$ at the same temperature and pressure and again weighed. The weight of oxygen will be:

• A. the same as that of ${SO}_2$
• B. one-half that of ${SO}_2$
• C. twice that of ${SO}_2$
• D. one-fourth that of ${SO}_2$

Answer 1

The correct option is B one-half that of ${SO}_2$

at NTP pressure, Temperature & R values

are constant for formula PV=nRT

so wt. (weight) totally depends on

their molecular weight

i.e. $\frac{M.wtof{O}_2}{M.wtofS{O}_2}=\frac{M_1}{M_2}=\frac{32}{64}=\frac{1}{2}$

$PV=\frac{weight}{Molarmass}\left(R\right)T$

$\Rightarrow$ weight of oxygen = $\frac{1}{2}S{O}_2$