Question

When a 30.98-g sample os phosphorus reacts with oxygen, a 71.00-g sample of phosphorus oxide is formed. What is the percent composition? What is the empirical formula?

Answer 1

30.98g / 71.00g * 100 gives you percent composition...
As for empirical you need to 1) write a balance equation , 2) find your amount of P and O.
3) Take lower amount (in moles) and divide the other variable by that number.
Those 2 numbers ( 1 and another , can be anything) will give you your empirical formula which should be in the form of (P)x(O)y

Answer 2

Alright, I got the percent composition (43.6338%), but I don't know where to start for the balance equation.

Answer 3

write your equation. So you have phosphorous + oxyygen yields phosphorus oxide. Balance it if needed