A bracelet containing 0.345 mol of metal atoms is 66% gold. How many particles of gold atoms are in the bracelet?

Question

A bracelet containing 0.345 mol of metal atoms is 66% gold. How many particles of gold atoms are in the bracelet?

Answer 1

Using dimensional analysis and the knowledge that there are 6.02x10²³ atoms in a mole (Avogadro's number)....

0.345 moles x 6.02x10²³ atoms/mole = 2.077x10²³ atoms

66% of these are gold, so we have 2.077x10²³ atoms x 0.66 = 1.37x10²³ gold atoms