How many particles are in 100.0 grams of gold

First, we need to convert the grams of gold into mole using the molar mass (molecular weight) of gold, and then into particles using avogadro's number (1 mol = 6.02 x 10^23)

molar mass of gold = 197 grams / mole

100.0 grams (1 mole / 197 grams) x (6.02 x 10^23 particles / 1 mole) = 3.06 x 10^23