How many Fe atoms are contained in 787 g of Fe?

1 Answer
Feb 27, 2018

#8.49xx10^24# #"atoms Fe"#


To determine the number of atoms in a certain mass of a substance, we need to convert the mass into units of moles by using the molar mass of the substance.

Then, we multiply Avogadro's constant, which represents the number of units in one mole of any substance. This has the value of #6.022 xx 10^23 "units/mol"#.

We do as follows:

#"787 g Fe" xx ("1 mol Fe" /"55.85 g" ) xx ( (6.022xx10^23 "atoms Fe") /"1 mol Fe" ) = 8.49xx10^24 "atoms Fe"#