The analysis of a compound containing K, P and O showed 55 % K, 15 % P and 30 % O, set up the simplest empirical formula of this compound.

Empirical formula is K₃PO₄.

Explanation:

Given data:

Percentage of K = 55%

Percentage of P = 15%

Percentage of O = 30%

Empirical formula = ?

Solution:

Number of gram atoms of K = 55 / 39.098 = 1.41

Number of gram atoms of P = 15 /30.974= 0.48

Number of gram atoms of O = 30 / 15.999 = 1.88

Atomic ratio:

             K                      :          P                   :         O

           1.41/0.48            :       0.48/0.48        :       1.88/0.48

               3                     :           1                    :            4

K : P : O = 3 : 1 : 4

Empirical formula is K₃PO₄.