Question

The density of solid Cu is 8.96 g/cm3. How many atoms are present per cubic centimeter of Cu?

Answer 1

The density is already given to you and it's telling you that there are a cubic centimeter of Cu has the mass of 8.96 g. First, you need to convert that to mols, using the following equation:\[mol=\frac { g }{ M_ r } \]

Once you know the mol value that corresponds to 8.96 grams, you need to convert the mole value in the number of atoms. There are always 6.022 x 10²³ atoms in one mole of substance. So you just need to multiply the Avagadro's number whatever you found as the mole value of 8.96 g of copper.