Question

A compound contains 74,27%C;7,79%H;12,99%N. Determine the empirical formula. C=12;H=1;N=14;0=16.

Answer 1

Assume you have 100 g sample; then,

mols C = 74.27/12 = ?
mols H = 7.79/1 = ?
mols N = 12.99/14 = ?
%O = 100-74.27-7.77-12.99 = 4.95%
mols O = 4.95/16 = ?

Now find the ratio of these elements to one another, round to whole numbers for the subscripts.