I'm gonna assume you want to find how much mass of oxygen 4.95g of phosphorus reacts with
Answer:
P4(s) + 502(8) --> 2P205(s)
We know that Phosphorus is polyatomic and Oxygen Gas is diatomic
Atomic mass of Phosphorus= 30.97g/mol
Atomic mass for Oxygen = 16g
4 * 30.97 = 123.88g
2 * 16 = 32g
Since there are 5 moles of oxygen: 5 * 32 = 160g
Ok, so 160g of oxygen will react 123.88g of Phosphorus
4.95g phosphorus burns with how much oxygen?
4.95 * 160g
123.88g
= 6.4g of Oxygen