A brown dye has a percent composition of 62.41% C, 5.24% H, and 32.36% N by mass with a molar mass of 346.40 g/mol. Determine the molecular formula of the dye

The molecular formula : C₁₈H₁₈N₈

Given

62.41% C, 5.24% H, and 32.36% N

Required

The molecular formula

Solution

mol ratio

C : 62.41/12.0096 = 5.1967

H : 5.24/1.00784 = 5.1992

N : 32.36/14.0067 = 2.310

Divide by 2.310(smallest)

C : 5.1967/2.31=2.25

H : 5.1992/2.31 = 2.25

N : 2.31/2.31 = 1

Multiplied by 4

C : H : N = 9 : 9 : 4

The empirical formula : C₉H₉N₄

(C₉H₉N₄)n=346.40 g/mol

(12.0096 x 9 + 1.00784 x 9 + 14.0067 x 4)n=346.4

(108.0864+9.07056+56.0268)n=346.4

(173.184)n=346.4

n=2

The molecular formula : C₁₈H₁₈N₈

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.