$A$ gas weighing $2.4 \ g$ has a vapor density of $11.2$. What is its volume in $L$ at $STP$?

$A$ pre-weighed vessel is filled with $O_2$ and weighed at $STP$. It is then evacuated and filled with $SO_2$ gas at the same temperature and pressure,and weighed again. The weight of $O_2$ will be:

At $T \ K$, $100 \ L$ of dry oxygen is present in a sealed container. It is subjected to silent electric discharge, until the volumes of oxygen and ozone become equal. What is the volume (in litres) of ozone formed at $T \ K$?

Find the mass of potassium chlorate required to liberate $5.6 \ dm^3$ of oxygen gas at $STP$. (Molar mass of $KClO_3 = 122.5 \ g/mol$) (in $g$)

Which solution is required to completely neutralize $25 \ mL$ of $N/10$ $NaOH$ solution?

$12 \ g$ of $Mg$ (atomic mass $24$) will react completely with acid to give: