Question

Determine the number of atoms of lead in a 2.938 g sample of pure lead.

Answer 1

1mole Pure lead =207.2 gm lead

1mole pure lead contains 6 022×10²³=1 avogadro number of pure lead atom

Then ,

207.2 gm lead contain 6.022×10²³ number of lead atoms

2.938 gm lead contain 6.022×10²³/207.2×2.938

=8.539×10²¹ number of lead atoms.