The weight of sodium carbonate required to prepare $500 \ mL$ of a semi-normal solution is .......... $g$.

For preparing a $0.1 \ N$ solution of a compound from its impure sample,where the percentage purity is known,the weight of the substance required will be:

What will be the volume of $4.4 \ g$ of $CO_2$ at $STP$ in liters?

The ratio of amounts of $H_2S$ needed to precipitate all the metal ions from $100 \ mL$ of $1 \ M$ $AgNO_3$ and $100 \ mL$ of $1 \ M$ $CuSO_4$ is

The reduction of boron trichloride $(BCl_3)$ by hydrogen yields elemental boron (atomic mass $10.8 \ g/mol$). If $21.6 \ g$ of boron is produced,what is the volume of hydrogen gas required at $273 \ K$ and $1 \ atm$ pressure (in $L$)?

Given the ratio of masses of nitrogen and oxygen in a particular gaseous mixture is $4: 1$. Calculate the ratio of the number of their molecules.