일반물리학 1 — Measurement: Problem 25

25 (a) Using the known values of Avogadro’s number and the atomic mass of sodium, find the average mass density of a sodium atom assuming its radius to be about 1.90 Å. (b) The density of sodium in its crystalline phase is 970 kg/m³. Why do the two densities differ? (Avogadro’s number, that is, the number of atoms or molecules in one mole of a substance, is \(6.023 \times 10^{23}\).)