Question: what is the empirical formula of a compound that is 43.6 phosphorus and 56.4 oxygen?
Answer: The correct answer to this question is D; the empirical formula for a compound that is 43.6% phosphorus and 56.4% oxygen is P2O5. In the formula, the P stands for phosphorus and the O standards for oxygen, so there are 2 phosphorus (P) atoms and 5 oxygen (O) atoms in the compound.