A forensic scientist is given a white substance that is thought to be cocaine. The substance is found to have a percent composition: 49.48% C, 5.19% H, 28.85% N, and 16.48% O. What is the empirical formula for this substance? Is it cocaine?

1 answer

Assume 100 grams
C=49.48grams=4.12 moles
H=5.19grams=5.19 moles H
N=28.85grams=2 moles
O-16.48grams-1 mole
Noticed I rounded on these, you need to do it more accurately. Now, divide all by the lowest mole number, in this case 1, so the numbers are the same.

Empirical formula
C4H5N2O
Nope, not Coke. no common multiplier to those subscripts for the actual compound will give C17H21NO4