The number of moles of a gas in $1 \, m^3$ of volume at $NTP$ is

Calculate the following for $3 \ mol$ of ethane $(C_2H_6)$:
$(i)$ Number of moles of carbon atoms
$(ii)$ Number of moles of hydrogen atoms
$(iii)$ Number of molecules of ethane

The mass of $1$ mole of electrons is

The total number of electrons present in $18 \ mL$ water (density $= 1 \ g/mL$) is

The molar mass of $CO_2$ is $44 \ g/mol$. Given that the Avogadro constant is $6.022 \times 10^{23} \ mol^{-1}$,the mass of one molecule of $CO_2$ is ..... $\times 10^{-23} \ g$.

The number of molecules in $16 \ g$ of methane is ...... $\times 10^{23}$.