CH3-(CH2)m-O-(CH2-CH2-O)n-H
sau
CH3-(CH2)m-1-CH2-O-(CH2-CH2-O)n-H
Cp Cs Cp Cp Cp
=>
3+2m+2+4n+1 = 78 => 2m+4n = 74/:2 = m+2n = 37
Cp/Cs = 11/8
avem
2+2n/m-1 = 11/8
=> 16+16n = 11m-11
m+2n = 37 => m = 37-2n
=> 16 + 16n = 11(37-2n) - 11
=> n = 380/38 = 10
=> m = 37-2x10 = 17
=> nr at. C = m + 2n = 17 + 20 = 37