Question: how many moles of magnesium phosphate will contain 0.25 mole of oxygen atom?
Answer: Answer. 1 mole of magnesium phosphate compound(Mg3(PO4)2) will contain 8 moles oxygen atom. So,moles of magnesium phosphate that contains 0.25 mole of oxygen atom= 0.25/8=0.03125 mol=3.1*10^-2 mol.