A compound with a percent composition by mass of 24.61% C, 2.75% H, and 72.64% Cl has a molar mass of 292.82 g/mol. What is the molecular formula of the compound

Question

Quizplus · Accepted Answer

1. Calculate the number of moles of each element:
- C: 24.61 g / 12.01 g/mol = 2.046 moles
- H: 2.75 g / 1.01 g/mol = 2.722 moles
- Cl: 72.64 g / 35.45 g/mol = 2.048 moles
2. Divide the number of moles of each element by the smallest number of moles to get the simplest whole-number ratio:
- C: 2.046 / 2.046 = 1
- H: 2.722 / 2.046 = 1.333 ≈ 4/3
- Cl: 2.048 / 2.046 = 1.000 ≈ 1
3. Multiply each of the subscripts by the smallest integer that makes all of them integers:
- C: 1 × 3 = 3
- H: 4/3 × 3 = 4
- Cl: 1 × 3 = 3
4. The molecular formula is C3H4Cl3.

A Compound with a Percent Composition by Mass of 24