Question

A compound is found to contain 39.99 % carbon, 6.727 % hydrogen, and 53.28 % oxygen by weight. To answer the questions, enter the elements in the order presented above. 1. What is the empirical formula for this compound

Answer 1

Answer:

CH₂O

Explanation:

The empirical formula is the simplest whole-number ratio of atoms in a compound.

The ratio of atoms is the same as the ratio of moles.

So, our job is to calculate the molar ratio of C:H:O.

Assume 100 g of the compound.

1. Calculate the mass of each element.

Then we have 39.99 g C, 6.727 g H, and 53.28 g O.

2. Calculate the moles of each element

$\text{Moles of C} = \text{39.99 g C} \times \dfrac{\text{1 mol C}}{\text{12.01 g C}} = \text{3.330 mol C}\\\\\text{Moles of H} = \text{6.727 g H} \times \dfrac{\text{1 mol H}}{\text{1.008 g H }} = \text{6.674 mol H}\\\\\text{Moles of O} = \text{53.28 g O} \times \dfrac{\text{1 mol O}}{\text{16.00 g O }} = \text{3.330 mol O}$

3. Calculate the molar ratio of the elements

Divide each number by the smallest number of moles

C:H:O = 3.330:6.674:3.330 = 1:2.004:1.000 ≈ 1:2:1

4. Write the empirical formula

EF = CH₂O