Answer
About 63.16% of Carbon.
Work Step by Step
1. Find the molar mass of Vanillin
$C_{8}H_{8}O_{3}$:
C: 12 x 8 = 96
H: 1 x 8 = 8
O: 16 x 3 = 48
96 + 8 + 48 = 152g/mol
2. Divide the mass of Carbon by the total mass of the molecule, and multiply the result by 100%:
$\frac{96}{152}$ x 100% $\approx$ 63.16%
