What is the mass of 5.31×1021 platinum atoms?

1.72 g

Explanation:

1) The atomic mass of an element is the mass of one mole of atoms.

2) One mole of atoms is 6.022×10²³ atoms (Avogadro's number).

3) The atomic mass of platinum is 195.078 grams / mole (from a periodic table)

4) Formulas:

number of moles = number of atoms / 6.022×10²³

mass in grams = number of moles × atomic mass

5) Calculations:

number of moles = 5.31×10²¹ atoms / 6.022×10²³ atoms/mole = 0.00882 moles

mass in grams = 0.08882 mol × 195.078 g/mol = 1.72 g

the answer is 75.0%.

plasma - state of matter made up of electrically charged particles