Question

What is the percent composition of hydrogen (H) in benzene (C6H6)?
1.321%
7.757%
15.38%
92.31%

Answer 1

@Astrophysics

Answer 2

composition by mass?

Look at your periodic table and find the atomic mass of C and H. Multiply the atomic mass of C by the number of atoms of C in a benzene molecule, multiply the atomic mass of H by the number of atoms of H in a benzene molecule, and add those two together to get the molecular mass of a benzene molecule. If you want the percent composition of one substance that makes up part of another, you find that with
\[\text{percent composition} = \frac{\text{mass of one substance}}{\text{mass of everything}} * 100\%\]