Answer
The molecular formula for Lysine will be:
$C_{6} H_{14} N_{2} O_{2} $
Work Step by Step
Initially, you assume that you are working with 100 grams of the sample.
Mass will then be:
N = 19.2 g; H = 9.64 g; C = 49.3 g; O = 21,9 g;
The second step will be to calculate the number of mole for each element:
N = 19.2/14 = 1.3714
H = 9.64/1 = 9.64
C = 49.3/12 = 4.10
O = 21.9/16 = 1.36875
The third step will be to dive by the smallest number of mole, in this case 1.36875.
C = 1.3714/1.36875 = 1.00 = 1
H = 9.64/1.36875 = 7.04 = 7
C = 4.10/1.36875 = 2.99 = 3
O = 1.36875/1.36875 = 1 = 1
Then the formula will be $C_3 H_7 N O$
because Lysine has 2 Nitrogen atoms, then all the number will be multiplied by 2. Thus, $C_6 H_{14} N_2 O_2 $
