The mass of nitrogen that combines with $40 \ g$ of oxygen in $N_2O_5$ is ............ $g$.

Commercial concentrated sulfuric acid is $95\% $ $H_2SO_4$ by weight. If the density of this commercial acid is $1.834 \ g \ cm^{-3}$,the molarity of this solution is ....... $M$.

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 $T \ K$?

How many moles of $H_2O_2$ are required to decolorize $1$ mole of $KMnO_4$ (in $.5$)?

$X$ litres of carbon monoxide is present at $STP$. It is completely oxidized to $CO_2$. The volume of $CO_2$ formed is $11.207$ litres. What is the value of $X$ in litres?

$A$ sample of $NaOH$ weighing $0.38 \ g$ is dissolved in water to make $50.0 \ mL$ of solution in a volumetric flask. What is the molarity of the resulting solution in $M$?