In some compound, the mass fraction of phosphorus is 43.66%, oxygen is 56.34%

In some compound, the mass fraction of phosphorus is 43.66%, oxygen is 56.34% Derive the simplest formula of the compound

Given:
ω (P) = 43.66%
ω (O) = 56.34%

To find:
the simplest formula is?

Decision:
1) Let m (PxOy) = 100 g;
2) m (P) = ω (P) * m (PxOy) / 100% = 43.66% * 100/100% = 43.66 g;
3) n (P) = m / M = 43.66 / 31 = 1.408 mol;
4) m (O) = ω (O) * m (PxOy) / 100% = 56.34% * 100/100% = 56.34 g;
5) n (O) = m / M = 56.34 / 16 = 3.521 mol;
6) x: y = n (P): n (O) = 1.408: 3.521 = 1: 2.5 = 2: 5.

Answer: The simplest formula is P2O5.