How many atoms in 1 cm3 of copper?

The density of copper (Cu) is about 8.92 g/cm3. So 1 cm3 of copper is about 8.92 g. Next find the number of moles in 8.92 g of copper by dividing by its molecular weight:

8.92 g Cu / 63.54 g/mol Cu = 0.14038 mol Cu

By definition 1 mol of any substance is Avogadro's number of atoms or, 6.022 x 10 23 atoms.

So, 0.14038 mol Cu * [6.022x1023 atoms Cu / mol Cu] = 8.45x1022 atoms of Cu