A white compound is analyzed and found to contain
43.64% phosphorous and 56.36% oxygen by mass.

What is the empirical formula?

In terms of moles, in 100.00 g of compound we have:
Empirical Formula Example
43.64g P x (1 mol P / 30.97g P) = 1.409 mol P

56.36 g O x (1 mol O / 15.99g O) = 3.523 mol O