mass of calcium oxide equals 89.23 g
molar mass of calcium oxide equals 56 G / Mole
the formula which is used as much of CaO equals molar mass of CaO
now put all of the Given values in this formula, we would get the moles of calcium oxide.
moles of CaO= 88.23g over 56g/mole which would get you 1.593 moles
