Answer
About 15.79% of Carbon.
Work Step by Step
The represented molecule is Thiourea ($C_{}H_{4}N_{2}S_{}$).
1. Find the molar mass of Thiourea:
C: 12 x 1 = 12
H: 1 x 4 = 4
N: 14 x 2 = 28
S: 32 x 1 = 32
12 + 4 + 28 + 32 = 76
2. Divide the mass of carbon in one molecule by the molar mass.
$\frac{12}{76}$ $\approx$ 0.1579
3. Multiply the result by 100%
0.1579 x 100% = 15.79%