Question

What is the chemical formula of an unknown compound that contains 60% carbon, 13.3% hydrogen, and 26.7% oxygen by mass, determined through elemental analysis?

Answer 1

To determine the chemical formula of the unknown compound, we can use the mass percentages to find the empirical formula. 1. Assume you have 100 grams of the compound. This means you have:   - 60 grams of Carbon  C    - 13.3 grams of Hydrogen  H    - 26.7 grams of Oxygen  O 2. Convert the mass of each element to moles:   - Carbon: 60 g / 12.01 g/mol  molar mass of C   5 moles   - Hydrogen: 13.3 g / 1.008 g/mol  molar mass of H   13.2 moles   - Oxygen: 26.7 g / 16.00 g/mol  molar mass of O   1.67 moles3. Divide each mole value by the smallest mole value to get the mole ratio:   - Carbon: 5 / 1.67  3   - Hydrogen: 13.2 / 1.67  7.9  approximately 8    - Oxygen: 1.67 / 1.67  14. The empirical formula is C3H8O.The chemical formula of the unknown compound is C3H8O.