What is the mass of 5.22×10^21 platinum atoms? ?

1.69g

Explanation:

To solve the problem you need to know the Avogadro´s number and the molar mass of the Platinum.

The Avogadro´s number is . For the platinum it means that there are atoms of platinum for each mol.

And the molar mass for the platinum is , that is the mass in grams of each mol of platinum.

So, with this information we can solve the problem as follows:

of Pt