Q 12.35 - An Introduction to General, Organic, and Biological Chemistry

Question

Oxybenzone is an effective sunscreen whose structural formula is shown. 

a. What functional groups are in oxybenzone? 

b. What is the molecular formula and molar mass of oxybenzone? 

c. If a bottle of sunscreen containing$178$ mL has$6.0$ (m/v) oxybenzone, how many grams of oxybenzone are present?

Step-by-Step Solution

Answer

(a) The functional groups present in the oxybenzone are thiol, ketone and alcohol.

(b) The molecular formula is$C_{14}{H}_{12}{O}_3$ and the molar mass is$228g/mol$.

(c) $10.68g$of oxybenzone are present.

Part (a) Step 1: Given information

We are given the compound and we have to find out the functional groups present in it.

Part (a) Step 2: Explanation

The compound oxybenzone contains${\mathrm{CH}}_3-\mathrm{O}-{\mathrm{CH}}_3,{\mathrm{CH}}_3-\mathrm{OH} \mathrm{and} {\mathrm{CH}}_3-\mathrm{C}\left(=\mathrm{O}\right)-{\mathrm{CH}}_3$ and in this first one is a thiol functional group, the second one is an alcohol functional group, and the third one is a ketonic group.

Hence, thiol, alcohol, and ketonic functional groups are present in oxybenzone.

Part (b) Step 1: Given information

We are given the compound and we have to find out the molecular formula and molar mass of this compound.

Part (b) Step 2: Explanation

The compound oxybenzone contains fourteen carbons, twelve hydrogens, and three oxygens, which states that the molecular formula of oxybenzone is ${\mathrm{C}}_{14}{\mathrm{H}}_{12}{\mathrm{O}}_3$and the molar mass of oxybenzone is$\mathrm{mass}= 14\times 12+12\times 1+3\times 16=228\mathrm{g}$.

Hence, the molecular formula is ${\mathrm{C}}_{14}{\mathrm{H}}_{12}{\mathrm{O}}_3$and the molar mass is $228g$. 

Part (c) Step 1: Given information

We are given the volume and mass per volume of oxybenzone and we have to find out the mass of oxybenzone.

Part (c) Step 2: Explanation

The bottle of sunscreen contains$178mL$ $6\%\left(m/v\right)$and to find out the mass

$m/v\%=\frac{mass of solute}{volume of solution}$

Putting the value we get, $\frac{6}{100}=\frac{mass}{178}$

On solving we get,$mass= 10.68g$.

Hence, the mass of oxybenzone is $10.68g$