Question: how many moles of magnesium phosphate will contain 0.25 mole of oxygen?
Answer: 3(po4)2, will contain 0.25 mole of oxygen atoms? 1 mole of Mg3(PO4)2 (molecule) contains 3 moles of Mg atoms, 2 moles of P atoms and 2X4 moles of O atoms. = 0.03125 moles.