Question:
Calculate the number of atoms in 39.4 g gold. Molar mass of gold is 197 g/mole.
Solution:
Molar mass = 6.023 × 1023 atoms
Mass of gold, m = 39.4 g
Molar mass of gold, M = 197 g/mol
196 g of gold contains 6.023 × 1023 atoms
39.4 g of gold contains 1.20 × 1023 atoms.