Question

which of these is an empirical formula?
$ce{co_{2}}$
$ce{c_{3}h_{6}}$
$ce{c_{2}o_{4}}$
$ce{c_{2}h_{4}o_{2}}$

Explanation:

Step1: Define empirical formula

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

Step2: Analyze $\text{CO}_2$

The ratio C:O is 1:2, which cannot be simplified further with whole numbers.

Step3: Analyze $\text{C}_3\text{H}_6$

The ratio C:H is 3:6, which simplifies to 1:2, so this is a molecular formula, not empirical.

Step4: Analyze $\text{C}_2\text{O}_4$

The ratio C:O is 2:4, which simplifies to 1:2, so this is a molecular formula, not empirical.

Step5: Analyze $\text{C}_2\text{H}_4\text{O}_2$

The ratio C:H:O is 2:4:2, which simplifies to 1:2:1, so this is a molecular formula, not empirical.

Answer:

$\text{CO}_2$