Question

7.An organic compound containing C, H and 0 gave the percentage composition C=40.687%,
H= 5.085% and O=54.228%Calculate the molecular formula of the compound. The molecular
mass of the compound is 118g.
​

Answer 1

Answer:

Basic →100 g of compound

masses M.M moles Ratios Ratio

C 403687 12 3.3916 3.4/3.4=1 2

H 5.085 1 5.085 5.1/3.4=1.5 3

O 54.228 16 3.392 3.4/3.4=1 2

Emperical formula =C

2

H

2

O

2

Emperical mass =2×12+3×1+2×16

=24+3+32

=59

molecular mass =2×vapor density

=2×59=118

n=

E.M

M.M

=

59

118

=2

molecular formula =n×E.F=2×C

2

H

3

O

2

=C

4

H

6

O

4