He ability to rust is a chemical property of iron. The metal silver does not rust, but eventually a darker substance called tarnish forms on its surface. The chemical properties of copper cause it to become a blue-green color when it is exposed to air
Number of moles = number of atoms/Avogadro's number
= (4.8x10^25)/(6.02x10^23)
=79.7 mol (3sf)
