Problem: The volume of a sphere is (4/3)πr3 and the density of copper is 8.96 g/cm3.What is the radius (in cm) of a pure copper sphere that contains 1.37 1024 copper atoms?

Recall that density is the ratio of the mass and volume of an object:

$\boxed{\mathbf{density}\mathbf{=}\frac{\mathbf{mass}}{\mathbf{volume}}}$

Also, the volume of a sphere is given by:

$\boxed{\mathbf{V}\mathbf{=}\frac{\mathbf{4}}{\mathbf{3}}{\mathbf{\pi r}}^{\mathbf{3}}}$

Avogadro’s number = 6.022 x 10²³ entities

                                      entities = atoms, ions, molecules, particles, formula units

Molar mass of Cu = 63.55 g/mol