Answer:
5.016 moles
Step-by-step explanation:
You find the molar mass of MgO by adding their atomic masses. so take out that periodic table.
24.31 g/mol + 16 g/mol = 40.31 g/mol
then follow this ideology:
number of moles = mass/molar mass
number of moles = 202.2 g / 40.31 g/mol
number of moles = 5.016 mol