Convert 4.50 moles of fe to atoms of fe

Avogadro's number represents the number of units in one mole of any substance. This has the value of 6.022 x 10^23 units / mole. This number can be used to convert the number of atoms or molecules into number of moles. We do as follows:

4.50 mol Fe ( 6.022x10^23 atoms / 1 mol Fe ) = 2.71x10^24 atoms Fe present 

C. definite shape, definite volume. that is a solid.