There are approximately 2.71 * 10^24 molecules in 4.5 moles of iron (ii) nitrite
We need to use Avogadro's number, which is approximately 6.022 * 10^23 molecules per mole.
The molecular formula of iron (ii) nitrite is Fe(NO2)2.
The formula to be used is: number of molecules = number of moles * Avogadro's number
Number of molecules = 4.5 moles * 6.022 * 10^23 molecules/mole
Number of Molecules = 2.71 * 10^24 molecules