Calculate the mass in gram of 2.01*10^10 atoms of Mg

First we need to convert the given atoms of Mg to units of moles. To do this, we divide the given with the Avogadros number.

Moles of Mg = number of atoms / Avogadro’s number

Moles of Mg = 2.01 x 10^10 atoms / (6.022 x 10^23 atoms / mol)

Moles of Mg = 3.33776 x 10^-14 mol Mg

Then we convert moles to mass by multiplying with the Molar mass. Molar mass of Mg = 24.305 g / mol

Mass of Mg = Moles of Mg * Molar mass of Mg

Mass of Mg = 3.33776 x 10^-14 mol * 24.305 g / mol

Mass of Mg = 8.11 x 10^-13 g