1. The sample contains 24.0 g of carbon, 3.0 g of hydrogen, and 32.0 g of oxygen.
2. Molar masses: C = 12.0 g/mol, H = 1.0 g/mol, O = 16.0 g/mol.
3. Moles of each element:
- Carbon: 24.0 g / 12.0 g/mol = 2.0 mol
- Hydrogen: 3.0 g / 1.0 g/mol = 3.0 mol
- Oxygen: 32.0 g / 16.0 g/mol = 2.0 mol
4. Divide each by the smallest number of moles (2.0):
- Carbon: 2.0 / 2.0 = 1
- Hydrogen: 3.0 / 2.0 = 1.5
- Oxygen: 2.0 / 2.0 = 1
5. Multiply by 2 to get whole numbers: C₂H₃O₂.
6. Empirical formula mass: (2 × 12.0) + (3 × 1.0) + (2 × 16.0) = 59.0 g/mol.
7. Molecular mass is 118.0 g/mol, so divide: 118.0 / 59.0 = 2.
8. Multiply empirical formula by 2: C₄H₆O₄.
9. The molecular formula is C₄H₆O₄.
Parent Tip: Review the logic above to help your child master the concept of chemistry unit 4 worksheet 2 answers.
