Question

Determine the empirical formulas for compounds with the following percent compositions:
(a) 43.6% phosphorus and 56.4% oxygen
(b) 28.7% K, 1.5% H, 22.8% P, and 47.0% O

Answer 1

(a) 43.6% phosphorus and 56.4% oxygen

100 g of compound will contain 43.6 g P and 56.4 g O. The atomic masses of P and O are 31 g/mol and 16 g/mol respectively.
The number of moles pf P mol
The number of moles of O mol
The mole ratio
The empirical formula is

(b) 28.7% K, 1.5% H, 22.8% P, and 47.0% O
100 g of compound will contain 28.7 g K, 1.5 g H, 22.8 g P and 47.0 g O.
The atomic masses of K, H, P and O are 39.1 g/mol , 1 g/mol , 31 g/mol and 16 g/mol respectively.
The number of moles of K mol
The number of moles of H mol
The number of moles of P mol
The number of moles of O mol
The mole ratio
The empirical formula is