The mass of $112 \ cm^3$ of $NH_3$ gas at $STP$ is (in $g$)

Which of the following contains the maximum number of atoms?

The mass of $2 \times 10^{22}$ nitrogen atoms is ..... grams.

In which of the following pairs do $1 \text{ g}$ of each contain the same number of molecules?
$(I)\, N_2O$ and $CO$               $(II)\,N_2$ and $CO_2$
$(III)\, N_2$ and $CO$                $(IV) \,N_2O$ and $CO_2$

How many moles are equivalent to $5.6 \ L$ of oxygen gas at $NTP$?

If $24 \times 10^{23}$ molecules are removed from $50 \ g$ of hydrogen gas $(H_2)$,how many moles of hydrogen remain?