Number of atoms present in $224 \, dm^3$ of oxygen gas at $STP$ is

How many water molecules are there in one drop of water $($Volume $= 0.0018 \ mL)$ at room temperature?

The number of atoms in $558.5 \ g$ of $Fe$ is equal to: [Atomic mass of $Fe = 55.85 \ g/mol$]

Number of atoms in $11.2 \, L$ of $CO_2$ at $NTP$ is .............. $N_A$

How many moles of nitrogen atoms are present in $8 \ g$ of ammonium nitrate (in $mol$)?

$A$ thin layer of cobalt is deposited on a plate with a total area of $0.5 \ m^2$ and a thickness of $0.005 \ cm$. How many cobalt atoms are deposited on the plate? (Density of cobalt $= 8.9 \ g \ cm^{-3}$,Atomic mass of $Co = 59 \ g \ mol^{-1}$)