What is the empirical formula for a compound that has the following mass percent composition:
C, 55.80%; H, 7.03%; O, 37.17%.

Question

Quizplus · Accepted Answer

To find the empirical formula, we assume a 100 g sample of the compound, which gives us the following masses:

- Mass of C: 55.80 g
- Mass of H: 7.03 g
- Mass of O: 37.17 g

Next, we use the molar masses of each element to convert the masses to moles:

- Moles of C: 55.80 g / 12.01 g/mol = 4.65 mol
- Moles of H: 7.03 g / 1.01 g/mol = 6.96 mol
- Moles of O: 37.17 g / 16.00 g/mol = 2.32 mol

We can then divide each of these mole values by the smallest mole value to get the simplest whole number ratio of atoms:

- C: 4.65 mol / 2.32 mol ≈ 2
- H: 6.96 mol / 2.32 mol ≈ 3
- O: 2.32 mol / 2.32 mol = 1

So the empirical formula is C2H3O. The only answer choice that matches this formula is C.

What Is the Empirical Formula for a Compound That Has