Problem: The density of solid Fe is 7.87 g/cm3. How many atoms are present per cubic centimeter of Fe? As a solid, Fe adopts a body-centered cubic unit cell. How many unit cells are present per cubic centimeter of Fe? What is the volume of a unit cell of this metal? What is the edge length of a unit cell of Fe?

FREE Expert Solution

molar mass Fe = 55.845 g/mol

1 mole = 6.022x1023 entities
entities = atoms, ions, molecules, formula units

density of solid Fe = 7.87 g/cm3


Calculate the atoms present per cubic centimeter of Fe

atomscm3=7.87 g Fecm3×1 mol Fe55.845 g Fe×6.022×1023 Fe atoms1 mol Fe

atoms/cm3 = 8.486x1022 Fe atoms/cm3


Calculate the number of unit cells are present per cubic centimeter of Fe

recall the # of atoms present per 1 BCC unit cell: corner atoms contribute 1/8 and the center atom contribute 1

# of atoms=8×18+1

# of atoms = 2 per 1 unit cell

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Problem Details

The density of solid Fe is 7.87 g/cm3. How many atoms are present per cubic centimeter of Fe? As a solid, Fe adopts a body-centered cubic unit cell. How many unit cells are present per cubic centimeter of Fe? What is the volume of a unit cell of this metal? What is the edge length of a unit cell of Fe?

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