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

The number of sodium ions present in $0.5 \ mol$ of sodium ferrocyanide is?

Which gas among the following contains the maximum number of molecules at $STP$? (Molar masses in $g \ mol^{-1}$: $CO_{2}=44, Ar=39.9, CH_{4}=16, O_{2}=32$)

Which of the following contains the maximum number of oxygen atoms?

What is the approximate weight of one molecule of methane $(CH_4)$?

How many molecules are present in one gram of hydrogen? (Value $\times 10^{23}$)