October 15, 2018 at 1:49 PM Dioxybenzone is a compound found in sunscreen, and only contains carbon, oxygen, and hydrogen. Analysis of the compound found that it contains 4.92% hydrogen and 26.18% oxygen. The molar mass of the compound is 244.25 g/mol. What is the molecular formula?

Molecular formula for Dioxybenzone is C₁₄H₁₂O₄

Explanation:

Percent composition:

In 100 g of compound → 4.92 g are H

In 100 g of compound → 26.8 g are O

In 100 g of compound → 68.28 g are C

Let's convert the mass to moles by molar mass:

4.92 g / 1 g/mol = 4.92 moles H

26.8 g / 16 g/mol = 1.67 moles O

68.28 g / 12 g/mol = 5.69 moles C

Now we can apply a rule of three:

100 g of compound have 4.92 moles H, 1.67 moles O, 5.69 moles C

244.25 g of compound must have:

(244.25 g. 4.92 m) / 100 g = 12 moles H

(244.25 g. 1.67 m) / 100 g = 4 moles O

(244.25 g. 5.69 m) / 100 g = 14 moles of C