Question

Referring to the molecular sketch and table above, choose the option that best describes the percentage of carbon in the molecule, in terms of both atomic composition and mass-percent composition.

• A. Carbon makes up approximately $25$% of the atoms, and $25$% of the mass.
• B. Carbon makes up approximately $40$% of the atoms, and $40$% of the mass.
• C. Carbon makes up approximately $25$% of the atoms, and $40$% of the mass.
• D. Carbon makes up approximately $40$% of the atoms, and $25$% of the mass.

Answer 1

The correct option is C Carbon makes up approximately $25$% of the atoms, and $40$% of the mass.

The molecular formula of compound $=C_4{H}_{9}N{O}_3$

$\%$ of carbon atom $=\frac{4}{4+9+1+3}=\frac{4}{17}\times 100\approx 25\%$

$\%$ of carbon by mass $=\frac{4\times 12}{48+9+14+48}=\frac{48}{119}\times 100=40.33\%$