the moles of magnesium does the sample contain is 2.469 moles
calculation
moles of Mg= mass of Mg /molar mass of Mg
mass of Mg = 60.0 g
From periodic table, the molar mass of Mg =24.3 g/mol
The moles of mg is therefore= 60.0 g / 24.3 g/mol = 2.469 moles