Consider a situation in which 136 g of p4 are exposed to 144 g of o2.what is the maximum number of moles of p2o5 that can theoretically be made from 136 g of p4 and excess oxygen?

First write a balanced equation...

 P4   +  5 O2   ⇒  2P2O5 

mole of  P4 = 136 ÷ (4×31) = 1.09677

MOLE RATION OF P4 : P2O5 IS 1:2
 THAT IS 1 mole of p4 reacts to give 2 moleof p2o5
∴ 1.09677 mole (2×1.09677) =2.19mole

maximum number of mole = 2.19 mol