Question

determina formula moleculara la o monoamina care contine 8.917% N si provine de la o arena cu NE=7

Answer 1

monoamina => 1 at de N cu masa de 14g/mol
M......................100%
14.....................8,917%
M=14×100/8,917=157g/mol
Notam formula moleculara CxHyN
N.E=[2+x(4-2)+y(1-2)+1(3-2)]/2=7
2+2x-y+1=14 => 2x-y=11 (I)
Pe de alta parte M=12x+y+14=157 => 12x+y=143 (II)
Avem un sistem, pe care il rezolvam
2x-y=11
12x+y=143
------(+)-------
14x / =154 => x=11
Insa din (I) => y=2x-11=22-11=11
formula moleculara: C₁₁H₁₁N