3.5. Elemental phosphorus burns in oxygen with an intensely hot flame, producing a brilliant light and clouds of the oxide product. These properties of the combustion of phosphorus have led to its being used in bombs and incendiary devices for warfare.
\[
\mathrm{P}_{4}(s)+5 \mathrm{O}_{2}(g) \rightarrow 2 \mathrm{P}_{2} \mathrm{O}_{5}(s)
\]
If 4.95 g of phosphorus is burned, what mass of oxygen does it combine with?