Determine the molecular formula of a compound that has a molar mass of 183.2 g mol^-1 and an empirical formula of C₂H₅O₂. A) C₂H₅O₂ B) C₆H₁₅O₆ C) C₃H₇O₃ D) C₄H₁₀O₄ E) C₈H₂₀O₈

Question

Quizplus · Accepted Answer

1. Determine the empirical formula mass:
- C: 1 x 12.01 g/mol = 12.01 g/mol
- H: 15 x 1.01 g/mol = 15.15 g/mol
- O: 12 x 16.00 g/mol = 192.00 g/mol
- N: 1 x 14.01g/mol = 14.01 g/mol
- S: 1 x 32.06 g/mol = 32.06 g/mol
Empirical formula mass = 265.23 g/mol

2. Divide the molar mass by the empirical formula mass to get the whole number ratio:
183.2 g/mol / 265.23 g/mol ≈ 0.68996
Round to nearest whole number:
C0.69S1U1B12.96H0.57S1U1B15.03O0.73N0.004

3. Multiply each subscript by 100 to get rid of decimals:
C68.996S99.482H57.427O73.027N0.396

4. Divide each subscript by the smallest subscript:
C1S1U1B16H1S1U1B115O1N0.004

So the molecular formula is CS1U1B16S1U1B0HS1U1B115S1U1B0OS1U1B16S1U1B0 which is answer choice B.

Determine the Molecular Formula of a Compound That Has a Molar