Answer
3.82 x 10¯23 g/atom
Work Step by Step
1) Calculate the average mass of one atom of Na:
22.99 g mol¯1 ÷ 6.022 x 1023 atoms mol¯1 = 3.82 x 10¯23 g/atom
2) Determine atoms in 1 cm3:
0.968 g / 3.82 x 10¯23 g/atom = 2.54 x 1022 atoms in 1 cm3
3) Determine volume of the unit cell:
(4.29 x 10¯8 cm)3 = 7.89 x 10¯23 cm3
4) Determine number of unit cells in 1 cm3:
1 cm3 / 7.89 x 10¯23 cm3 = 1.27 x 1022 unit cells
5) Determine atoms per unit cell:
2.54 x 1022 atoms / 1.27 x 1022 unit cells = 2 atoms per unit cell
