Question

A compound of C, H and Ncontains 66.70%carbon,7.41%hydrogen and 25.90%nitrogen.The molecular mass of the compound was found to be 108
Find the empirical and molecular formula of the compound

Answer 1

Answer:

Molecular formula:  $\\\tt C_{6}H_{8}N_{2}$

Empirical formula:  $\\\tt C_{3}H_{4}N_{1}$

Logic:

Find mass of each element $\\\tt \longrightarrow$ Find number of atoms of each element in the compound

Calculation:

Given mass of molecule = 108amu.

Mass of C = 66.70% of Mass of compound =  72.036 amu ≈ 72amu

Mass of H= 7.41% of Mass of compound =  8.0028 amu ≈ 8 amu

Mass of N= 25.90% of Mass of compound =  27.972 amu ≈ 28 amu

No of atoms of C in compound  = 72/12 = 6

No of atoms of H in compound  = 8/1= 8

No of atoms of N in compound  = 28 /14 = 2

Therefore the molecular formula must be,

$\\\tt \longdownarrow$$\\\tt C_{6}H_{8}N_{2}$

Therefore empirical formula  $\\\tt C_{3}H_{4}N_{1}$