Answer:
Step-by-step explanation:
I'm using approximate molecular masses.
3 * C = 3 * 12 = 36
10*H = 10* 1 = 10
4*N = 4 *14 = 56
4*O = 4 * 16 = 64
================
Total = 166
Molecular Mass = 166
% Carbon = 36/166 * 100 = 21.7
Carbon = 21.7%
My atomic masses are approximate because all periodic tables are different. Re do the problem using the numbers off your periodic table.