1. Convert Percentages to Grams

Assume you have 100 grams of the compound. This means you have:

* 31.9 grams of potassium (K)

* 28.9 grams of chlorine (Cl)

* 39.2 grams of oxygen (O)

2. Convert Grams to Moles

Divide the mass of each element by its molar mass:

* Potassium (K): 31.9 g / 39.10 g/mol = 0.816 mol

* Chlorine (Cl): 28.9 g / 35.45 g/mol = 0.816 mol

* Oxygen (O): 39.2 g / 16.00 g/mol = 2.45 mol

3. Find the Simplest Mole Ratio

Divide each mole value by the smallest mole value (which is 0.816 in this case):

* Potassium (K): 0.816 mol / 0.816 mol = 1

* Chlorine (Cl): 0.816 mol / 0.816 mol = 1

* Oxygen (O): 2.45 mol / 0.816 mol = 3

4. Write the Empirical Formula

The empirical formula represents the simplest whole-number ratio of atoms in a compound. Based on our calculations:

The empirical formula is KClO₃.