4p + 5O2 -> P4O10 ; the percent yield of PO4O10 when 6.20 g of phosphorus burns into excess oxygen is 67.0%. What is the yiel

36.9 g. The balanced equation is P4 + 5O2 = P4O10. The moles of P4 present are calculated as 23.9 g x 1 mole/123.88 g = 0.193 moles. The moles of O2 available are 20.8 g x 1 mol/32 g = 0.65 moles O2. According to the balanced equation, the mole ratio of O2 to P4 is 5:1. Therefore, is 0.65 moles O2 equal to 5 times 0.193 moles? The answer is NO, indicating insufficient O2 is available. O2 is thus the limiting reactant. The theoretical moles of P4O10 produced equal 0.65 moles O2 multiplied by 1 mole P4O10 over 5 moles O2, resulting in 0.13 moles P4O10. Consequently, the mass of P4O10 generated equals 0.13 moles times 283.9 g, which is 36.9 g.