Calculate the molecular weight of the following.

${\mathrm{NH}}_3$.

Calculate the mass of the following-

$5 moles$ of ammonia.

Calculate the mass of the following-

Calculate the mass of the following-

$= 1.50 \mathrm{moles} {\mathrm{Na}}^{+}$ ion.

Calculate the mass of the following-

$0.2 moles$ of oxygen atoms.

Calculate the number of moles in the following:

$12 \mathrm{g}$ of ${\mathrm{O}}_2$

Calculate the number of moles in the following:

$22 \mathrm{g}$ of ${\mathrm{CO}}_2$

Determine the chemical formula of the following using the crisscross method.

Iron sulphate.

Determine the chemical formula of the following using the crisscross method.

Copper nitrate.