1. Assume a 100-gram sample:

* This makes the calculations easier. You have 88.8 grams of copper (Cu) and 11.2 grams of oxygen (O).

2. Convert grams to moles:

* Divide the mass of each element by its molar mass:

* Cu: 88.8 g / 63.55 g/mol = 1.39 mol

* O: 11.2 g / 16.00 g/mol = 0.70 mol

3. Find the mole ratio:

* Divide each mole value by the smallest mole value (0.70 mol):

* Cu: 1.39 mol / 0.70 mol = 1.99 ≈ 2

* O: 0.70 mol / 0.70 mol = 1

4. Write the empirical formula:

* The mole ratio gives you the subscripts in the formula: Cu₂O

Therefore, the empirical formula for the compound is Cu₂O.