1. **State the problem:** Calculate the relative formula mass of carbon dioxide (CO₂). 2. **Formula used:** The relative formula mass is the sum of the relative atomic masses of all atoms in the formula. 3. **Given data:** - Carbon (C) atomic mass = 12 - Oxygen (O) atomic mass = 16 4. **Calculate:** - CO₂ has 1 carbon atom and 2 oxygen atoms. - Relative formula mass = $1 \times 12 + 2 \times 16$ 5. **Simplify:** - $12 + 32 = 44$ 6. **Answer:** The relative formula mass of CO₂ is **44**. This means one molecule of carbon dioxide has a mass relative to 44 times the mass of one-twelfth of a carbon-12 atom.