A chemical compound is found to have the following composition: 
C = 19.57% ; Fe = 15.2% ; N = 22.83% ; and K = 42.39%
Calculate the empirical formula of the compound. What will be its molecular formula if the compound's molecular mass is 368?
Solution:
Step 1- Finding the empirical formula
The empirical formula, listing the elements present and in what percentages, provides the first detail about the compound. 
The empirical formula is calculated in four steps summarized below-

The compound's empirical formula is K4FeC6N6, which is written according to Hill nomenclature, which positions electropositive elements before other elements.
Step 2- Calculation of empirical formula mass
The next step is to calculate the empirical formula mass,
Empirical formula mass of K4FeC6N6 = 4 x 39 + 55.84 + 6 x 12 + 6 x 14 = 156 + 55.84 + 72 + 84 = 367.84
Step 3- Finding the value of n
The value of n is obtained by dividing the empirical formula mass by the molecular mass of the sample.

= 368/367.84 ~ 1
This means that the empirical and the molecular formula is the same for the compound, that is, K4FeC6N6.
K4FeC6N6 can also be expressed as K4Fe(CN)6, also known as Potassium ferrocyanide.
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Empirical Formula (subscribers only premium article)
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Hill nomenclature (free)
