Answer:
%
Step-by-step explanation:
Please see the complete question in the attachment
The given formula of Ibuprofen consists of 13 atoms of carbon, 18 atoms of hydrogen and 2 atoms of oxygen.
The atomic mass of carbon, hydrogen and oxygen is 12, 1 and 16 respectively.
The total atomic mass of Ibuprofen is equal to
![= ( 12 * 13) + ( 1 * 18) + ( 2* 16) \\= 156 + 18 + 32\\= 206](https://img.qammunity.org/2021/formulas/biology/high-school/52qhdzdqfgjoo4ybefk2ihaw1llftw208v.png)
Percent composition of hydrogen by mass is equal to atomic mass of hydrogen divided by total mass of Ibuprofen.
![(18)/(206) * 100\\= 8.74](https://img.qammunity.org/2021/formulas/biology/high-school/o3twlin6zgrq4yo4gtcgvlq180u2v9uny0.png)