A mixture of 156.3 g of P and 161.5 g of O2 reacts completely to form P4O6 and P4O10 . Find the masses of P4O6 and P4O10 that are formed by the reaction.

Answer 1

First, you should write a correctly balanced equation. Unfortunately, phosphorous doesn't really exist as P, but usually as P4 (white phosphorous). If you are asked to use just P, as in P + O2, then you would have the following balanced equation:

4P + 3O₂ ==> P₄O₆ and...

4P + 5O₂ ==> P₄O₁₀

----------------------------------------

8P + 8O₂ ==> P₄O₆ + P₄O₁₀ ... overall equation

moles of P present = 156.3 g x 1 mole/30.97 g = 5.047 moles P

moles O₂ present = 161.5 g x 1 mol/32 g = 5.047 moles O₂

Since the balanced equation shows a mole ratio of P to O₂ of 1:1, neither reactant is limiting.

5.047 mol P x 1 mol P₄O₆/8 mol P x 219.88 g/mol P₄O₆ = 138.7 g P₄O₆ formed

5.047 mol P x 1 mol P₄O₁₀/8 mol P x 283.89 g/mol P₄O₁₀ = 179.1 g P₄O₁₀ formed