How can I calculate the empirical formula of an oxide?
You calculate the molar ratios of each element in the oxide.
When a 2.50 g sample of copper is heated, it forms 3.13 g of an oxide. What is its empirical formula.
Step 1. Determine the masses
Mass of Cu = 2.50 g
Mass of O = (3.13 – 2.50) g = 0.63 g
Step 2. Determine the moles
Moles of Cu = 2.50 g Cu ×
Moles of O = 0.63 g O ×
Step 3. Determine the Molar Ratios
Step 4. Write the Empirical Formula
The empirical formula of the oxide is CuO.