What is the empirical formula of a compound composed of 72.36% Fe and 27.64% O by mass? empirical formula:

Empirical formula = Fe₃O₄

Explanation:

Given data:

Percentage of Fe = 72.36%

Percentage of oxygen = 27.64%

Empirical formula = ?

Solution:

Number of gram atoms of O = 27.64 / 16 = 1.7

Number of gram atoms of Fe = 72.36 / 55.8 = 1.3

Atomic ratio:

                          Fe                    :         O

                           1.3/1.3              :     1.7/1.3

                              1                    :       1.3            

Fe : O = 1 : 1.3

Empirical formula = 3( 1: 1.3)

Empirical formula = Fe₃O₄

"record the time to complete a chemical reaction" would most likely be part of a lab procedure.