Step 1
Empirical formula definition:
In chemistry, the empirical formula of a chemical compound is the simplest whole-number ratio of atoms present in a compound.
-----------------
Step 2
Information provided:
Composition,
50.7 % C
9.9 % H
39.4 % N
-----------------
Step 3
Assuming a 100 grams sample:
50.7 % C => 50.7 g C
9.9 % H => 9.9 g H
39.4 % N => 39.4 g N
-----------------
Step 4
The number of moles of each element is calculated as:
(Please, use your periodic table)
50.7 g C x (1 mole C/12.01 g C) = 4.22 moles C
9.9 g H x (1 mole H/1.008 g H) = 9.82 moles H
39.4 N x (1 mole N/14.00 g N) = 2.81 moles N
-----------------
Step 5
Each number in step 4 will be divided by the smallest one of the 3. It is also needed integer numbers.
4.22 moles C/2.81 moles N = 1.5
9.82 moles H/2.81 moles N = 3.5
2.81 moles N/2.81 moles N = 1
As we need integer numbers, we will multiply all these numbers by 2 as it follows:
C => 1.5 x 2 = 3
H => 3.5 x 2 = 7
N => 1 x 2 = 2
Therefore, the empirical formula will be:
Answer:
[tex]C_3H_7N_2[/tex]