1. The problem statement, all variables and given/known data The atomic mass of iron (Fe) is approximately 56 grams per mole. (a) Assume each iron atom in a bar of iron takes up a volume equal to a sphere of radius 2.35×10-10 m. Calculate the density of iron based on this model. (b) The actual density of iron is 7870 kg/m^3. Modify the atomic radius in (a) such that the calculated density agrees with the actual value. 2. Relevant equations Density = mass/(4/3)[tex]\pi[/tex]r^3 ( D=m/V ) 3. The attempt at a solution I figured out a) to be 1.71E3 kg/m^3. However, I can't figure out b). The new radius is 1.41E-9 from what I calculated , but it is not the right answer.