how many grams of diphosphorus pentoxide can be formed from 750 grams of oxygen

Answer 1

First thing, we must write a correctly balanced equation for the reaction of phosphorous (P) and oxygen (O₂) to form phosphorous pentoxide (P₂O₅)

4P + 5O₂ ==> 2P₂O₅

Now we convert grams O₂ to moles O₂, then moles O₂ to moles P₂O₅ and finally moles P₂O₅ to grams P₂O₅.

moles O₂ present = 750 g O₂ x 1 mol O₂ / 32 g = 23.4 mols O₂

moles P₂O₅ formed = 23.4 mols O₂ x 2 mols P₂O₅ / 5 mols O₂ = 9.38 mols P₂O₅

grams P₂O₅ = 9.38 mols P₂O₅ x 142 g P₂O₅ / mol = 1332 g P₂O₅ = 1300 g P₂O₅ (2 sig. figs.)