Question

Calculate the mass, in grams, of 502 atoms of iron ,Fe (1 mol of Fe has a mass of 55.85g).

Answer 1

mass of iron in grams = 1.493×
`10^(-23)` g

Step-by-step explanation:

Since one mole of anything is equal to 6.022×
`10^(23)` of that thing, we can apply that to atoms as well. 1 mol of iron = 55.85g. i.e. the molar mass of iron = 55.85g/mol.

To find the number of moles present, we can divide the number of atoms by the number of atoms in 1 mole, i.e Avogadro's Constant (6.022×
`10^(23)`).

`(N)/(N_(A)) = n`

∴ n(Fe) = 502/6.022×
`10^(23)` = 8.3361×
`10^(-22)` mol of iron

Finally, to find the mass of iron present, we can divide the number of moles by the molar mass.

`(n)/(M)} = m`

∴ m(Fe) = 8.3361×
`10^(-22)`/55.85 = 1.493×
`10^(-23)` g. (4 sig. fig.)