4P + 5O2 = P4O10 the molar ratio of P to O2 = 4:5 moles of P reacting with 0.114 mol of O2 = (0.114 mol/5)x4 = 0.0912 mol Solution 4P + 5O2 = P4O10 the molar ratio of P to O2 = 4:5 moles of P reacting with 0.114 mol of O2 = (0.114 mol/5)x4 = 0.0912 mol.