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

How many moles of methane are required to produce $22 \ g$ of $CO_2 \ (g)$ after combustion (in $mol$)?

$510 \ mg$ of a liquid on vaporisation in Victor Mayer's apparatus displaces $510 \ cm^3$ of dry air (at $NTP$). The molecular weight of the liquid is:

$A$ person consumes $640 \, g$ of $O_2$ daily. If all the $O_2$ is used for the conversion of sugar into $CO_2$ and $H_2O$,how much sucrose $(C_{12}H_{22}O_{11})$ is consumed in the body per day and how much heat in $kJ$ is produced (in $.33$)? Given: $\Delta H_{combustion} \text{ of sucrose} = -5645 \, kJ \, mol^{-1}$.

The volume (in $mL$) of $0.1\, N$ $NaOH$ required to neutralize $10\, mL$ of $0.1\, N$ phosphinic acid is........

On electrical decomposition of $150 \ mL$ dry and pure $O_2$,$10\%$ of $O_2$ gets changed to $O_3$. The volume of the gaseous mixture after the reaction and the volume of the remaining gas left after passing through turpentine oil will be,respectively: